Start with the first five chapters in the LAB book. It will get you moving really fast. Then its a toss up about whether to proceed with PP or LAB. Both books tend to get more difficult as you get further in. If you start with the LAB book, you will never understand why other people say that LAB is not an intuitive color space.
Duffy
Agreed. And to amplify. What you get with the first 5 chapters of the LAB book is a recipe that you can apply to a large class of photos without thinking terribly hard about what you're doing, in my opinion. In PP, you get some principles that Dan believes are necessary for any photo to be as good as it can be, and some techniques to apply them. No recipes, just lots of examples in how to apply the principles.
For a many (myself included, at first encounter), it was easier to understand the LAB color space than the CMYK space, which is ever-present in the PP books, as the target audience is professionals who have to produce finished products in that space. It turns out that CMYK isn't actually that hard, but I had a mental block on it for a while.
As Duffy said, both books get much harder in the second half. They both move to photos where the rules don't apply, are harder to apply, or there are specialized problems.
That said, maybe the first 5 chapters of LAB, followed by the first N chapters of PP (traveling, don't have it with me, but it's about 5), then wherever your interest takes you.
By he way, Dan has several videos now on Kelby Training (http://www.kelbytraining.com/), to which my only connection is that of a satisfied customer (except for bandwidth issues, another topic). He has a completely new workflow, which he has shown at Photoshop World, and which he is showing in a series of 3 videos (the first of which is available, but not the other 2 at this point). If you're willing and able to spring for the subscriptions, I'd recommend skipping the 2 LAB videos (as they're rather advanced), but following the other 3 on the new workflow. Extremely practical, and sort of recipe oriented, in the sense that he's offering a kind of formula for getting the best out of a large class of photos, with a fair amount of evaluation required in the process. The LAB videos are great also, but they presume a fair amount of background.
Thanks for the tips guys. The books should be here next Tuesday so I can get to it. I've avoided what has been written in this thread (and the related ones) until I read a portion of the books on my own.
I'm sure I will be back though.
http://www.bitartifact.com/
Canon 7D & 350D
10-22mm f/3.5-4.5 ~ 18-55mm f/3.5-5.6 II ~ 50mm f/1.8 II ~ 85mm f/1.8 ~ 100mm f/2.8 ~ 70-200mm f/4 IS L
Margulis, resolution, and Epson printer settings
Hello everyone,
Looks like no one has posted on this topic in a while. Hopefully someone can still offer their advice. For the past few years, on and off, I've been reading Margulis' prof. color correction book. I think I'm getting the hang of it.
In the Sharpening with a Stiletto chapter, he mentions that when working with USM it is really important to have the proper resolution to make sure what you see on the screen will be in the final print. I'd like to get the best possible print-outs with my current equipment.
Here is my setup....
Sony A100 camera (3872 x 2592 pixels @ 240 pixels/inch, Adobe RGB 1998 @ 8 bits/channel)
Printer: Epson 1280 (2880 dpi x 720 dpi max; 1440 dpi x 720 dpi typical)
Current intended print size: 5.35 inches x 8 inches
So, 2592 pixels x 3872 pixels to be printed at 5.35 inches x 8 inches = 484 pixels / inch resolution --> too high (I guess I should be aiming for 240 ppi or 360 ppi as a multiple of 720?).
So, if I would follow Margulis' advice, I would resample down to 1928 x 2880 pixels (360 ppi) or 1285 x 1920 pixels (240 ppi) before doing color corrections & USM? Is this correct? Hate to resample when I'm not too happy with the visual range as it is.
If anyone has other recommendations for using Margulis' techniques and printing to an Epson 6 ink printer, I'd love to hear them. Specifically:
- Color Management Setting: PhotoEnhance4 or No Color Adjustment?
- Print Quality: Fine, Photo, Best Photo, or Photo RPM? I'm not too impressed with the Epson documentation regarding what these choices really mean.
- CMYK conversion settings: SWOP v2, Gray Gamma 2.2, 20%, Preserve All Embedded Profiles, Adobe (ACE), Intent: Perceptual, Black Point Compensation, Use Dither
I believe that before printing, I should always convert my CMYK file to RGB to be most compatible with Epson's print driver.
Margulis idea you can visually interpret sharpening is bogus, that’s why. Also, every output device requires differing sharpening based on its pixel dimensions and output device. You simply can’t treat a 35mb image going to an ink jet the same as a 50mb image going to a halftone dot. And output sharpening, which is (or should be for anyone who targets to different devices) is based on capture sharpening which is based on the full rez master. Anyway, the Fraser article and later his book is the most flexible way to handle all this and has been incorporated into both Lightroom and ACR.
- Color Management Setting: PhotoEnhance4 or No Color Adjustment?
- Print Quality: Fine, Photo, Best Photo, or Photo RPM? I'm not too impressed with the Epson documentation regarding what these choices really mean.
- CMYK conversion settings: SWOP v2, Gray Gamma 2.2, 20%, Preserve All Embedded Profiles, Adobe (ACE), Intent: Perceptual, Black Point Compensation, Use Dither
I believe that before printing, I should always convert my CMYK file to RGB to be most compatible with Epson's print driver.
Any advice / direction?
1. Ideally use color management (Application Manages Color) in the host application using a good ICC profile of that device (Epson supplies very good canned profiles). That will allow you to also soft proof (something far more reliable visually on screen assuming good profiles for display and printer). Then in the driver, use No Color Adjustments.
2. Photo RPM (dumb term) is for that printer the “best quality” for images. It will be a bit slower.
3. Forget CMYK all together. This output device expects RGB data. If you send it CMYK, it will have a hissy fit and make one butt ugly print. GDI and Quickdraw drivers don’t understand CMYK.
When converting using an ICC profile (in this case to an RGB output device or one that expects RGB), the rendering intent is something you’ll pick based on your visual preference while toggling the two primary options (Perceptual or Relative Colorimetric) viewing the soft proof. Profiles don’t know squat about images. And each profile building package will produce a different rendering using the Perceptual intent. The profile making software, much like the difference you see in film stocks is based on what they feel you’ll like. Use ACE, use Black Point Compensation (it either helps or does nothing) and dither.
Thanks for the suggestions. I will be try to eliminate some of the variables and find a good working method.
I'm following you, arodney, except for #3 "Forget CMYK". His book is about how to color correct, largely using the advantages inherent in CMYK. I will check out Fraser's 3 step sharpening method and see if maybe both methodologies can be employed.
I can see some dramatic differences by following Margulis' technique with CMYK curves/sharpening. Initially it seemed a bit crazy to go from RGB input to CMYK and then back to RGB-based output but if it works... "Color correction by the numbers" seems to be a good system but it does seem to hit a conceptual snag when he talks about the visual analysis required with the USM step.
It sounds LAB correction doesn't alter the RGB gamut to I'll have to read up more on that but for now I think I'm correcting in CMYK and have to deal with the conversion settings.
Here's another question perhaps someone out there might be able to assist with...
After USM on a single channel, I see Edit, Fade Unsharp Mask. But, in the dialog box under Mode, Luminosity is grayed out. The only time I can select Mode: Luminosity is if I have applied an USM on the entire CMYK image. Why is this?
katheo, I think it is a misconception that Dan advocates converting *all* images into CMYK for curves or sharpening or other moves, just as I think it is a misconception that Dan advocates using Lab mode for *all* sharpening moves. Dan often notes pros and cons of different modes for different edits for different image content and when/why one may select to change modes or why they may not wish to.
seems to be a good system but it does seem to hit a conceptual snag when
he talks about the visual analysis required with the USM step.
Other common alternatives appear to be applying a sharpening setting and then doing a test print (which one may end up doing with other methods anyway), while another common approach is to use a non visual pre-made sharpening solution that has been devised by a third party and putting your trust in that (and then doing a test print and tweaking).
Here's another question perhaps someone out there might be able to
assist with... After USM on a single channel, I see Edit, Fade Unsharp
Mask. But, in the dialog box under Mode, Luminosity is grayed out. The
only time I can select Mode: Luminosity is if I have applied an USM on
the entire CMYK image. Why is this?
Luminosity blend mode is computed from the composite of the full colour channels, so it is not available on single channels. What you would need to do is use a separate layer, sharpen the single channel on the duped layer and then set the duped layer to luminosity blend mode.
I'm following you, arodney, except for #3 "Forget CMYK". His book is about how to color correct, largely using the advantages inherent in CMYK.
I don’t know if Dan’s ever used an ink jet printer like you refer to. He’s a press guy. You absolutely do not want to send CMYK to such a device. Give it a try.
Also, do you have any idea of the color gamut of such a device and how much of it you are throwing away, along with a lot of other data, to convert to CMYK? CMYK is an output specific color space. That means its solely designed for printing on a very specific device with a very specific flavor of CMYK.
Initially it seemed a bit crazy to go from RGB input to CMYK and then back to RGB-based output but if it works... "Color correction by the numbers" seems to be a good system but it does seem to hit a conceptual snag when he talks about the visual analysis required with the USM step.
Your initial instincts were good. Sure it looks ‘better’ if it didn’t no one would use it more than once. That doesn’t mean there are far better ways to work with the data with less hoops to jump through and without the time and data loss.
It sounds LAB correction doesn't alter the RGB gamut to I'll have to read up more on that but for now I think I'm correcting in CMYK and have to deal with the conversion settings.
Sure it does. And in 8-bit, depending on the original color space, it throws away a lot of data needlessly.
After USM on a single channel, I see Edit, Fade Unsharp Mask. But, in the dialog box under Mode, Luminosity is grayed out. The only time I can select Mode: Luminosity is if I have applied an USM on the entire CMYK image. Why is this?
Now if you stayed in RGB, you’d be able to fade using luminosity and you’d have all the advantages of converting to Lab and sharpening the Lstar channel. Its not 100% identical but it solves the issue faster, with far less damage to the image and with more control (with opacity).
Seriously, unless you have a true CMYK workflow, or have existing CMYK files or piss poor RGB turds to fix, you’ll find far more modern and flexible ways to achieve your goal (like getting really good, high bit, wide gamut, excellent appearing images out of Lightroom or ACR, especially if the source data is a digital capture and better, raw data).
Andrew,
The question katheo asked was about a print 5 x 8 inches - Is how one performs output sharpening a critical part of preparing images 5 x 8 inches for printing?
I sharpen in RAW processing to correct for the loss of acuity due to digitization. I print in LR due to its ease of use, over Photoshop, and use the output sharpening in LR, and find my images quite satisfying even up to 24 x 36 inches.
I do not ruminate on sharpening that much, as it seems to just not be an issue with the workflow I have described. Am I missing something?
I do use High pass and local contrast enhancements as needed by my eye also.
Andrew,
The question katheo asked was about a print 5 x 8 inches - Is how one performs output sharpening a critical part of preparing images 5 x 8 inches for printing?
But that’s not enough information for ideal (proper) output sharpening. Its a start. 5x8 at 200ppi would be treated differently than 5x8 at 480ppi. Output to an ink jet is different than output to a halftone device which is different than output to a contone device. If ink jet, matt or glossy paper?
I sharpen in RAW processing to correct for the loss of acuity due to digitization.
Which is the best place to be doing this (which is capture sharpening). Its totally non destructive. Since its just metadata, its real fast. If the raw converter you use improves the sharpening algorithms (something we’ve seen in various version of Lightroom and ACR), no harm, no foul.
I print in LR due to its ease of use, over Photoshop, and use the output sharpening in LR, and find my images quite satisfying even up to 24 x 36 inches.
Which again is ideal and a far more modern approach than what is being advised. That is output sharpening. You don’t have to do anything but specify the size. LR “knows” the pixel density. Now the output sharpening is based on ink jet usage and you do have to specify matt or glossy. To season to taste, you can have three “strengths”. But its pretty bloody brain dead easy, again non destructive, based upon the capture sharpening in the Develop module. Its imaging for the 21st century. Compared to opening a document in Photoshop and, god forbid, converting to CMYK or Lab, and then having to wrestle with the print dialog. In LR, its all set in a user template if properly configured, you simply select the “Print One” button and you’re done. No additional dialogs, stuff to set etc. The print module in LR is worth the price of admission. I know some (like Mac Holbert at Nash Editions) that use LR just to print!
Am I missing something?
Nope. Some people think that if they do a 27 step, complicated group of Photoshop moves, they will get better results. It helps sell books. It does make some feel digital macho. Some would rather spend countless hours ‘fixing’ an image that isn’t broken had they rendered the data properly in the raw converter in the first place. The more color space moves, the better. But then some like to work on cars with points rather than electronic ignition. Fine. For those that want to shoot, or make prints without all the hoops, there’s no reason to subscribe to a lot of the stuff discussed in the book named in this post. It is useful if you charge by the hour, or as I’ve said, someone handed you a truly awful image and that’s all they can supply. But ultimately GIGO:Garbage In Garbage Out rules.
katheo, I think it is a misconception that Dan advocates converting *all* images into CMYK for curves or sharpening or other moves, just as I think it is a misconception that Dan advocates using Lab mode for *all* sharpening moves. Dan often notes pros and cons of different modes for different edits for different image content and when/why one may select to change modes or why they may not wish to. http://prepression.blogspot.com/
True indeed. Its usually something along the lines of “sometimes this will work but sometimes it will not” meaning its hit or miss, try it you may like it but if not, its not the fault of this technique. Having flexible fudge factoring means you never have to say the technique is wrong.
Or can you find any writings where there is anything really definitive about conversion to Lab or CMYK, for the purpose of sharpening (and what kind of sharpening to what device)? Just what constitutes image content? Its a good tactic for those who sell contract proofs and charges customers for them. The rest of us have to pay for our media.
Thanks for the discussion. I am trying to absorb it all.
I realize that the success of any method is definitely dependent on the visual characteristics of a particular image. Net result is that I would like to get to the point where I can personally make excellent inkjet prints without a major waste of supplies *and* also provide clients with image files that would be magazine-ready.
My plan was to read the Professional Photoshop book which primarily focuses on the benefits of CMYK corrections (just about finished), then go on to the LAB book to add to my repertoire. There is very little mention of staying in RGB entirely so I assumed that wasn't really an option. Any recommendations on good books for entirely RAW/RGB-based corrections?
Or can you find any writings where there is anything really definitive about conversion to Lab or CMYK, for the purpose of sharpening (and what kind of sharpening to what device)? Just what constitutes image content? Its a good tactic for those who sell contract proofs and charges customers for them. The rest of us have to pay for our media.
Dan's major theme is that color correction in CMYK offers benefits because two color plates often dominate an image. By identifying the 'unwanted color' plate and zeroing in on its corrections, you get the biggest bang for your 'correction' buck. In the chapter "In Color Correction, the Key is in the K" he also talks about RGB & LAB and how each color is uniquely defined in those colorspaces. He then goes on to talk about the gamut expansion that happens when adding a 4th variable K thereby allowing each color to have multiple ink combination possibilities. So, if I am following him correctly, the color transformation provides a flexibility which makes it easier to fine tune the image.
Of course, he is press output focused and does not delve into outputting to inkjet RGB-based devices (at least in my early book edition). So, it is unclear whether CMYK conversion should have any part of a RGB-input/RGB-output workflow. I believe that he would contend that the correction benefits of CMYK would outweigh colorspace conversion issues.
I haven't gotten to the LAB book yet. But, I did read that conversion to LAB and back again in 16-bit is lossless on the wikipedia page http://en.wikipedia.org/wiki/Lab_color_space. I was assuming that you could take an 8-bit, convert to 16-bit, convert to LAB, do corrections, and then back to RGB without any color degradation. The increased file size for 16-bit images would be a significant drawback for this workflow.
Andrew, I read your article and thought I was getting it all. Then I hit the last sentence where you suggest providing sRGB images to clients (!). Everything I've read seems to suggest that sRGB is best for monitor/web use and Adobe RGB better for print. Can you explain? Perhaps I need to read "Part 2" of your article.
Andrew, I read your article and thought I was getting it all. Then I hit the last sentence where you suggest providing sRGB images to clients (!). Everything I've read seems to suggest that sRGB is best for monitor/web use and Adobe RGB better for print. Can you explain?
Clients that don't understand color management. Giving them a wider gamut file will only confuse them.
But, I did read that conversion to LAB and back again in 16-bit is lossless on the wikipedia page http://en.wikipedia.org/wiki/Lab_color_space. I was assuming that you could take an 8-bit, convert to 16-bit, convert to LAB, do corrections, and then back to RGB without any color degradation.
The wikipedia doesn't say that its lossless because its not. It implies that its moot (as I said) because you have so much data to begin with. And Dan don't believe in high bit workflows despite the best efforts of the manufacturers of capture and output devices as well as Adobe products among others. http://www.brucelindbloom.com/index.html?DanMargulis.html
At least unlike Dan and others, the site does correctly write the color model as Lab, like raw isn't an acronym.
The wikipedia doesn't say that its lossless because its not. It implies that its moot (as I said) because you have so much data to begin with. And Dan don't believe in high bit workflows despite the best efforts of the manufacturers of capture and output devices as well as Adobe products among others. http://www.brucelindbloom.com/index.html?DanMargulis.html
At least unlike Dan and others, the site does correctly write the color model as Lab, like raw isn't an acronym.
OK, so the transformation between RGB/Lab color space will involve some unrecoverable color/data shift although it might not be perceptible. Perhaps the wikipedia page should be clearer? As a beginner, I find the last two sentences in the second paragraph under "Advantages of Lab" confusing in this regard: "In the 1990s, when computer hardware and software was mostly limited to storing and manipulating 8 bit/channel bitmaps, converting an RGB image to Lab and back was a lossy operation. With 16 bit/channel support now common, this is no longer such a problem."
Does LR offer wide radius sharpening these days (radius > 10 and maybe 50 or more?) This kind of sharpening at very low opacity or amount makes a huge visual difference, one that often adds a lot of impact to a picture. It is also much more sensitive to the content of the photograph and much less sensitive to output size and resolution.
This is a baby that shouldn't get thrown out with the bath, Andrew.
I find local contrast enhancement quite worthwhile as well, John, but I do not know how to do that except in Photoshop, myself either.
Isn't the Clarity control in Lightroom something similar (not the exact same, but aimed at the same issue)? This is what Jeff Schewe says about it here:
Clarity
The word says it all…this new control (one that I’m very fond of since I personally begged and pleaded with Thomas Knoll to put in) is a hybrid of using USM at a low amount and high radius-called Local Contrast Enhancement in an article by Michael Reichmann quoting a technique mentioned by Thomas-and a technique called MidTone Contrast Adjustment taught by Mac Holbert of Nash Editions
High (wide) Radius Low Amount sharpening is not the same thing as clarity - although both have a wider radius and lower amount than other common sharpening methods. Clarity type settings have a far, far greater radius and/or amount setting and or different opacity settings.
It should be noted that Andrew and Dan have a history of not agreeing with each other and that Andrew does not appear to be unbiased when it comes to commenting on Dan.
And here was Dan's reply from 2004 on the topic linked above by Andrew:
Date: Thu, 11 Nov 2004 23:17:43 EST From: Dan Margulis
Subject: Re: 16 Bit images only into LAB color space
Bill Morse writes,
Thanks for this reference, Andrew. I would love to see Dan’s response.
I find the whole topic so distasteful that I ordinarily pay no attention when it arises, but since it has come up I will make one post, but no more.
I have no objection to people who disagree with my opinions, even when they aren’t particularly civil about it; that’s how things get sorted out eventually.
The site in question is a different animal. It involves a frustrated individual deliberately posting information that he knows to be false. Plus, Andrew Rodney, who knows full well that the page is a troll, repeatedly posts links to it.
Bruce Lindbloom’s whole contention is that before I tested the 16-bit images, I converted them to 8-bit and then reconverted them to 16-bit before applying curves. If that were true, it would be like a test comparing how well two washing machines work on the same kind of load, except that one of them had a bucket of mud poured in it first.
Of course, it’s ridiculous. What he is seizing on and deliberately misinterpreting is a phrase in my original description of how I would proceed. I said I would run a series of drastic corrections on two copies of each of many, many files. One set of corrections would be done entirely in 16-bit and the conversion to 8-bit would come only at the end; then, on a copy of the file, I would convert to 8-bit immediately and load the identical actions, whereupon I would compare the two.
Makes sense so far, but I added: if it turns out that the version done in 16-bit is significantly better, then, and only then, I’d run a third test—converting the 8-bit file back to 16-bit before correcting it, to see if there wasn’t something about the calculation method that was producing the better result, rather than just the extra data.
I’ve studied what happens when you do that, and it’s pretty interesting. However, it never was any part of my testing of the images, for the simple reason that the corrections done in 16-bit all the way were never any better than in 8-bit, regardless of how drastic they were.
Bruce asked a lot of questions about this at the time, including correspondence with me off-list. I was aware then that he was trolling, because he was professing to be neutral on the subject, whereas on the ColorSync list he had recently called 16-bit correction “a must” in certain circumstances. So, when I saw he was trying to poke a hole in the methodology, I made sure that he grasped completely what the purpose of the hypothetical 16>8>16 conversion was.
There is no possibility that he misunderstood this; indeed, he could not possibly be so stupid as to think that anyone would perform a test this way. Nevertheless, he chose to post what he did, knowing that it was false.
While the content of the page collapses when this is understood, there is one other side note. Bruce accuses me of keeping the results to myself and appointing myself the sole judge, which he knows perfectly well is not true. I printed 10 pages of side-by-side samples in my current book, many at extreme magnifications. The versions are not identified until a box later in the chapter, and readers are invited to judge for themselves which is which, plus, I indicate how I voted when I first saw the proofs and did not know which was which. The original 16-bit files, and the corrections I applied to them, are all on the book’s CD and anybody who likes can either verify what I did or do their own experiments.
What prompted the accusation was an unfortunate incident involving my first round of tests. The test files were provided by a list member whom I did not know at the time. After I performed the tests, I was flabbergasted to learn that he would not give me permission to exhibit the images and results publicly, which I thought was the whole point of the exercise. He did confirm, several times, on this list and at least two others, that he and I were not personally acquainted; that he believed I did not realize he was not giving permission; and that he had seen my results and that I was describing them accurately. When Bruce challenged him, he offered to give him pieces of the pictures (and my results) that would have been sufficient for Bruce to verify the findings, but Bruce refused to take them.
Because of this incident, I changed the rules. I said I would not do any testing on 16-bit files without an advance agreement enabling me to publish them and to release the raw data to illustrate whatever was found. Ric Cohn and a couple of other people kindly agreed to allow their images to be used in this fashion. Consequently the files are available for anybody on the CD.
The upshot of this: you guessed it. With the rules now having been altered to accommodate Bruce, Bruce wrote that the test was invalid, because the rules had been changed.
In summary: the issue with the page is not its dishonesty as much as its irrelevance. Bruce is the one advocating the inconvenient workflow, just as it would be if he said that there’s a big quality difference if one only wears garlic around the neck while booting Photoshop up. Nobody can disprove that, because if your tests show that there’s no difference, probably the garlic was too old or there wasn’t enough of it.
Similarly, nobody can disprove that 16-bit correction may be better under some circumstances, because nobody can test every conceivable image with every conceivable tool. However, the only two people who have ever run extensive tests—Jim Rich and I—tortured the images almost beyond belief and still were not able to identify any areas in which 16-bit correction did better with a color photograph.
It’s painfully apparent at this point that Bruce and the others have never actually done side-by-side tests to support their theories. Otherwise, we’d have seen examples long ago. For anybody wishing to successfully advocate the 16-bit workflow, the recipe is quite easy:
1) Here is a photographic image;
2) Here is what I did to it in 16-bit;
3) If you convert it to 8-bit first and then repeat what I did, it looks a lot worse.
Without that demonstration, he has put up a blank page, IMHO.
OK, so the transformation between RGB/Lab color space will involve some unrecoverable color/data shift although it might not be perceptible. Perhaps the wikipedia page should be clearer? As a beginner, I find the last two sentences in the second paragraph under "Advantages of Lab" confusing in this regard: "In the 1990s, when computer hardware and software was mostly limited to storing and manipulating 8 bit/channel bitmaps, converting an RGB image to Lab and back was a lossy operation. With 16 bit/channel support now common, this is no longer such a problem."
Its not a problem in 16-bit but the conversions are still not lossless. In fact any alteration of original data in any color model results in data loss due to rounding errors (and there are no Lab or CMYK capture devices).
Every time a conversion to LAB is produced, the rounding errors and severe gamut mismatch between the two spaces can account for data loss, known as quantization errors. The amount of data loss depends on the original gamut size and gamma of the working space. For example, if the working space is Adobe RGB, which has 256 values available, converting to 8- bit LAB reduces the data down to 234 levels for neutrals. The net result is a loss of 22 levels. Doing the same conversions from ProPhoto RGB reduces the data to only 225 values, producing a loss of 31 levels. Bruce Lindbloom, a well-respected color geek and scientist, has a very useful Levels Calculator,which allows you to enter values to determine the actual number of levels lost to quantization (see the “Calc page”at http://www.brucelindbloom.com).
As for Dan's ideas on high bit, the Lindbloom URL above sums it up. Dan keeps moving the goal posts and is in a state of denial. Bruce is a real world, actual color scientist who uses science instead of flat earth theories obfuscation to prove his points.
katheo, Dan's Lab book goes into topic of converting from RGB to Lab mode in in chapter 6. One analogy used was in translating from French to English back to French.
Although Dan has Lab (only) mode workflows and uses Lab mode for specific parts of his "Picture Postcard Workflow" - he generally only advocates changing to another colour mode for a good reason. The good reason may be that it is quicker or easier to do something in one mode than the other or that the results are judged better by the end user when performed in one mode when compared to another.
Additionally, there are often ways that one can take advantage of the other colour mode while limiting mode conversion effects (if one is concerned) - such as using blending modes or masks and a duped copy of the original image.
he generally only advocates changing to another colour mode for a good reason. The good reason may be that it is quicker or easier to do something in one mode than the other or that the results are judged better by the end user when performed in one mode when compared to another.
His specifics of quicker and easier usually boils down to your mileage may vary (he's not specific).
Quicker, easier, and without data loss is rendering the ideal pixels from raw versus fixing a turd unless that's all you have. I've said from day one, if you are presented such lemons, some of Dan's techniques do result in tastily if not overly difficult to produce lemonaid! Dan's ideas of raw processing (setting ACR sliders to zero and then fixing the resulting turd) is his M.O. Its silly but the minions buy into it for some odd reasons.
I'm presently in Quito but off to the Galapagos islands in the morning to hopefully shoot more ideal raw data to render, there's no net access so I'm not ignoring you all <g>. Please continue.
Comments
+1 on LAB
For a many (myself included, at first encounter), it was easier to understand the LAB color space than the CMYK space, which is ever-present in the PP books, as the target audience is professionals who have to produce finished products in that space. It turns out that CMYK isn't actually that hard, but I had a mental block on it for a while.
As Duffy said, both books get much harder in the second half. They both move to photos where the rules don't apply, are harder to apply, or there are specialized problems.
That said, maybe the first 5 chapters of LAB, followed by the first N chapters of PP (traveling, don't have it with me, but it's about 5), then wherever your interest takes you.
By he way, Dan has several videos now on Kelby Training (http://www.kelbytraining.com/), to which my only connection is that of a satisfied customer (except for bandwidth issues, another topic). He has a completely new workflow, which he has shown at Photoshop World, and which he is showing in a series of 3 videos (the first of which is available, but not the other 2 at this point). If you're willing and able to spring for the subscriptions, I'd recommend skipping the 2 LAB videos (as they're rather advanced), but following the other 3 on the new workflow. Extremely practical, and sort of recipe oriented, in the sense that he's offering a kind of formula for getting the best out of a large class of photos, with a fair amount of evaluation required in the process. The LAB videos are great also, but they presume a fair amount of background.
John Bongiovanni
I'm sure I will be back though.
Canon 7D & 350D
10-22mm f/3.5-4.5 ~ 18-55mm f/3.5-5.6 II ~ 50mm f/1.8 II ~ 85mm f/1.8 ~ 100mm f/2.8 ~ 70-200mm f/4 IS L
What happened to this great topic?
M
Hello everyone,
Looks like no one has posted on this topic in a while. Hopefully someone can still offer their advice. For the past few years, on and off, I've been reading Margulis' prof. color correction book. I think I'm getting the hang of it.
In the Sharpening with a Stiletto chapter, he mentions that when working with USM it is really important to have the proper resolution to make sure what you see on the screen will be in the final print. I'd like to get the best possible print-outs with my current equipment.
Here is my setup....
Sony A100 camera (3872 x 2592 pixels @ 240 pixels/inch, Adobe RGB 1998 @ 8 bits/channel)
Printer: Epson 1280 (2880 dpi x 720 dpi max; 1440 dpi x 720 dpi typical)
Current intended print size: 5.35 inches x 8 inches
So, 2592 pixels x 3872 pixels to be printed at 5.35 inches x 8 inches = 484 pixels / inch resolution --> too high (I guess I should be aiming for 240 ppi or 360 ppi as a multiple of 720?).
So, if I would follow Margulis' advice, I would resample down to 1928 x 2880 pixels (360 ppi) or 1285 x 1920 pixels (240 ppi) before doing color corrections & USM? Is this correct? Hate to resample when I'm not too happy with the visual range as it is.
If anyone has other recommendations for using Margulis' techniques and printing to an Epson 6 ink printer, I'd love to hear them. Specifically:
- Color Management Setting: PhotoEnhance4 or No Color Adjustment?
- Print Quality: Fine, Photo, Best Photo, or Photo RPM? I'm not too impressed with the Epson documentation regarding what these choices really mean.
- CMYK conversion settings: SWOP v2, Gray Gamma 2.2, 20%, Preserve All Embedded Profiles, Adobe (ACE), Intent: Perceptual, Black Point Compensation, Use Dither
I believe that before printing, I should always convert my CMYK file to RGB to be most compatible with Epson's print driver.
Any advice / direction?
Yup, read this (and probably ignore most of what you’ve PREVIOUSLY read):
http://www.creativepro.com/story/feature/20357.html
Author "Color Management for Photographers"
http://www.digitaldog.net/
So why read it if one should ignore what you've just read?
Stephen Marsh
http://members.ozemail.com.au/~binaryfx/
http://prepression.blogspot.com/
http://members.ozemail.com.au/~binaryfx/
http://prepression.blogspot.com/
Margulis idea you can visually interpret sharpening is bogus, that’s why. Also, every output device requires differing sharpening based on its pixel dimensions and output device. You simply can’t treat a 35mb image going to an ink jet the same as a 50mb image going to a halftone dot. And output sharpening, which is (or should be for anyone who targets to different devices) is based on capture sharpening which is based on the full rez master. Anyway, the Fraser article and later his book is the most flexible way to handle all this and has been incorporated into both Lightroom and ACR.
Author "Color Management for Photographers"
http://www.digitaldog.net/
1. Ideally use color management (Application Manages Color) in the host application using a good ICC profile of that device (Epson supplies very good canned profiles). That will allow you to also soft proof (something far more reliable visually on screen assuming good profiles for display and printer). Then in the driver, use No Color Adjustments.
2. Photo RPM (dumb term) is for that printer the “best quality” for images. It will be a bit slower.
3. Forget CMYK all together. This output device expects RGB data. If you send it CMYK, it will have a hissy fit and make one butt ugly print. GDI and Quickdraw drivers don’t understand CMYK.
When converting using an ICC profile (in this case to an RGB output device or one that expects RGB), the rendering intent is something you’ll pick based on your visual preference while toggling the two primary options (Perceptual or Relative Colorimetric) viewing the soft proof. Profiles don’t know squat about images. And each profile building package will produce a different rendering using the Perceptual intent. The profile making software, much like the difference you see in film stocks is based on what they feel you’ll like. Use ACE, use Black Point Compensation (it either helps or does nothing) and dither.
As for color settings in general: http://www.ppmag.com/reviews/200404_rodneycm.pdf
Author "Color Management for Photographers"
http://www.digitaldog.net/
I'm following you, arodney, except for #3 "Forget CMYK". His book is about how to color correct, largely using the advantages inherent in CMYK. I will check out Fraser's 3 step sharpening method and see if maybe both methodologies can be employed.
I can see some dramatic differences by following Margulis' technique with CMYK curves/sharpening. Initially it seemed a bit crazy to go from RGB input to CMYK and then back to RGB-based output but if it works... "Color correction by the numbers" seems to be a good system but it does seem to hit a conceptual snag when he talks about the visual analysis required with the USM step.
It sounds LAB correction doesn't alter the RGB gamut to I'll have to read up more on that but for now I think I'm correcting in CMYK and have to deal with the conversion settings.
Here's another question perhaps someone out there might be able to assist with...
After USM on a single channel, I see Edit, Fade Unsharp Mask. But, in the dialog box under Mode, Luminosity is grayed out. The only time I can select Mode: Luminosity is if I have applied an USM on the entire CMYK image. Why is this?
Stephen Marsh
http://members.ozemail.com.au/~binaryfx/
http://prepression.blogspot.com/
http://members.ozemail.com.au/~binaryfx/
http://prepression.blogspot.com/
Other common alternatives appear to be applying a sharpening setting and then doing a test print (which one may end up doing with other methods anyway), while another common approach is to use a non visual pre-made sharpening solution that has been devised by a third party and putting your trust in that (and then doing a test print and tweaking).
Luminosity blend mode is computed from the composite of the full colour channels, so it is not available on single channels. What you would need to do is use a separate layer, sharpen the single channel on the duped layer and then set the duped layer to luminosity blend mode.
Regards,
Stephen Marsh
http://members.ozemail.com.au/~binaryfx/
http://prepression.blogspot.com/
http://members.ozemail.com.au/~binaryfx/
http://prepression.blogspot.com/
I don’t know if Dan’s ever used an ink jet printer like you refer to. He’s a press guy. You absolutely do not want to send CMYK to such a device. Give it a try.
Also, do you have any idea of the color gamut of such a device and how much of it you are throwing away, along with a lot of other data, to convert to CMYK? CMYK is an output specific color space. That means its solely designed for printing on a very specific device with a very specific flavor of CMYK.
Your initial instincts were good. Sure it looks ‘better’ if it didn’t no one would use it more than once. That doesn’t mean there are far better ways to work with the data with less hoops to jump through and without the time and data loss.
Sure it does. And in 8-bit, depending on the original color space, it throws away a lot of data needlessly.
Because you’re in the devils color space <g>.
See:http://www.ppmag.com/reviews/200703_rodneycm.pdf
Now if you stayed in RGB, you’d be able to fade using luminosity and you’d have all the advantages of converting to Lab and sharpening the Lstar channel. Its not 100% identical but it solves the issue faster, with far less damage to the image and with more control (with opacity).
Seriously, unless you have a true CMYK workflow, or have existing CMYK files or piss poor RGB turds to fix, you’ll find far more modern and flexible ways to achieve your goal (like getting really good, high bit, wide gamut, excellent appearing images out of Lightroom or ACR, especially if the source data is a digital capture and better, raw data).
Author "Color Management for Photographers"
http://www.digitaldog.net/
The question katheo asked was about a print 5 x 8 inches - Is how one performs output sharpening a critical part of preparing images 5 x 8 inches for printing?
I sharpen in RAW processing to correct for the loss of acuity due to digitization. I print in LR due to its ease of use, over Photoshop, and use the output sharpening in LR, and find my images quite satisfying even up to 24 x 36 inches.
I do not ruminate on sharpening that much, as it seems to just not be an issue with the workflow I have described. Am I missing something?
I do use High pass and local contrast enhancements as needed by my eye also.
Moderator of the Technique Forum and Finishing School on Dgrin
But that’s not enough information for ideal (proper) output sharpening. Its a start. 5x8 at 200ppi would be treated differently than 5x8 at 480ppi. Output to an ink jet is different than output to a halftone device which is different than output to a contone device. If ink jet, matt or glossy paper?
Which is the best place to be doing this (which is capture sharpening). Its totally non destructive. Since its just metadata, its real fast. If the raw converter you use improves the sharpening algorithms (something we’ve seen in various version of Lightroom and ACR), no harm, no foul.
Which again is ideal and a far more modern approach than what is being advised. That is output sharpening. You don’t have to do anything but specify the size. LR “knows” the pixel density. Now the output sharpening is based on ink jet usage and you do have to specify matt or glossy. To season to taste, you can have three “strengths”. But its pretty bloody brain dead easy, again non destructive, based upon the capture sharpening in the Develop module. Its imaging for the 21st century. Compared to opening a document in Photoshop and, god forbid, converting to CMYK or Lab, and then having to wrestle with the print dialog. In LR, its all set in a user template if properly configured, you simply select the “Print One” button and you’re done. No additional dialogs, stuff to set etc. The print module in LR is worth the price of admission. I know some (like Mac Holbert at Nash Editions) that use LR just to print!
Nope. Some people think that if they do a 27 step, complicated group of Photoshop moves, they will get better results. It helps sell books. It does make some feel digital macho. Some would rather spend countless hours ‘fixing’ an image that isn’t broken had they rendered the data properly in the raw converter in the first place. The more color space moves, the better. But then some like to work on cars with points rather than electronic ignition. Fine. For those that want to shoot, or make prints without all the hoops, there’s no reason to subscribe to a lot of the stuff discussed in the book named in this post. It is useful if you charge by the hour, or as I’ve said, someone handed you a truly awful image and that’s all they can supply. But ultimately GIGO:Garbage In Garbage Out rules.
Author "Color Management for Photographers"
http://www.digitaldog.net/
True indeed. Its usually something along the lines of “sometimes this will work but sometimes it will not” meaning its hit or miss, try it you may like it but if not, its not the fault of this technique. Having flexible fudge factoring means you never have to say the technique is wrong.
Or can you find any writings where there is anything really definitive about conversion to Lab or CMYK, for the purpose of sharpening (and what kind of sharpening to what device)? Just what constitutes image content? Its a good tactic for those who sell contract proofs and charges customers for them. The rest of us have to pay for our media.
Author "Color Management for Photographers"
http://www.digitaldog.net/
I realize that the success of any method is definitely dependent on the visual characteristics of a particular image. Net result is that I would like to get to the point where I can personally make excellent inkjet prints without a major waste of supplies *and* also provide clients with image files that would be magazine-ready.
My plan was to read the Professional Photoshop book which primarily focuses on the benefits of CMYK corrections (just about finished), then go on to the LAB book to add to my repertoire. There is very little mention of staying in RGB entirely so I assumed that wasn't really an option. Any recommendations on good books for entirely RAW/RGB-based corrections?
Dan's major theme is that color correction in CMYK offers benefits because two color plates often dominate an image. By identifying the 'unwanted color' plate and zeroing in on its corrections, you get the biggest bang for your 'correction' buck. In the chapter "In Color Correction, the Key is in the K" he also talks about RGB & LAB and how each color is uniquely defined in those colorspaces. He then goes on to talk about the gamut expansion that happens when adding a 4th variable K thereby allowing each color to have multiple ink combination possibilities. So, if I am following him correctly, the color transformation provides a flexibility which makes it easier to fine tune the image.
Of course, he is press output focused and does not delve into outputting to inkjet RGB-based devices (at least in my early book edition). So, it is unclear whether CMYK conversion should have any part of a RGB-input/RGB-output workflow. I believe that he would contend that the correction benefits of CMYK would outweigh colorspace conversion issues.
I haven't gotten to the LAB book yet. But, I did read that conversion to LAB and back again in 16-bit is lossless on the wikipedia page http://en.wikipedia.org/wiki/Lab_color_space. I was assuming that you could take an 8-bit, convert to 16-bit, convert to LAB, do corrections, and then back to RGB without any color degradation. The increased file size for 16-bit images would be a significant drawback for this workflow.
Andrew, I read your article and thought I was getting it all. Then I hit the last sentence where you suggest providing sRGB images to clients (!). Everything I've read seems to suggest that sRGB is best for monitor/web use and Adobe RGB better for print. Can you explain? Perhaps I need to read "Part 2" of your article.
Katherine (aka katheo)
Clients that don't understand color management. Giving them a wider gamut file will only confuse them.
Author "Color Management for Photographers"
http://www.digitaldog.net/
The wikipedia doesn't say that its lossless because its not. It implies that its moot (as I said) because you have so much data to begin with. And Dan don't believe in high bit workflows despite the best efforts of the manufacturers of capture and output devices as well as Adobe products among others. http://www.brucelindbloom.com/index.html?DanMargulis.html
At least unlike Dan and others, the site does correctly write the color model as Lab, like raw isn't an acronym.
Author "Color Management for Photographers"
http://www.digitaldog.net/
OK, so the transformation between RGB/Lab color space will involve some unrecoverable color/data shift although it might not be perceptible. Perhaps the wikipedia page should be clearer? As a beginner, I find the last two sentences in the second paragraph under "Advantages of Lab" confusing in this regard: "In the 1990s, when computer hardware and software was mostly limited to storing and manipulating 8 bit/channel bitmaps, converting an RGB image to Lab and back was a lossy operation. With 16 bit/channel support now common, this is no longer such a problem."
This is a baby that shouldn't get thrown out with the bath, Andrew.
Moderator of the Technique Forum and Finishing School on Dgrin
Clarity
The word says it all…this new control (one that I’m very fond of since I personally begged and pleaded with Thomas Knoll to put in) is a hybrid of using USM at a low amount and high radius-called Local Contrast Enhancement in an article by Michael Reichmann quoting a technique mentioned by Thomas-and a technique called MidTone Contrast Adjustment taught by Mac Holbert of Nash Editions
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Stephen Marsh
http://members.ozemail.com.au/~binaryfx/
http://prepression.blogspot.com/
http://members.ozemail.com.au/~binaryfx/
http://prepression.blogspot.com/
And here was Dan's reply from 2004 on the topic linked above by Andrew:
Stephen Marsh
http://members.ozemail.com.au/~binaryfx/
http://prepression.blogspot.com/
http://members.ozemail.com.au/~binaryfx/
http://prepression.blogspot.com/
Its not a problem in 16-bit but the conversions are still not lossless. In fact any alteration of original data in any color model results in data loss due to rounding errors (and there are no Lab or CMYK capture devices).
Every time a conversion to LAB is produced, the rounding errors and severe gamut mismatch between the two spaces can account for data loss, known as quantization errors. The amount of data loss depends on the original gamut size and gamma of the working space. For example, if the working space is Adobe RGB, which has 256 values available, converting to 8- bit LAB reduces the data down to 234 levels for neutrals. The net result is a loss of 22 levels. Doing the same conversions from ProPhoto RGB reduces the data to only 225 values, producing a loss of 31 levels. Bruce Lindbloom, a well-respected color geek and scientist, has a very useful Levels Calculator,which allows you to enter values to determine the actual number of levels lost to quantization (see the “Calc page”at http://www.brucelindbloom.com).
As for Dan's ideas on high bit, the Lindbloom URL above sums it up. Dan keeps moving the goal posts and is in a state of denial. Bruce is a real world, actual color scientist who uses science instead of flat earth theories obfuscation to prove his points.
Author "Color Management for Photographers"
http://www.digitaldog.net/
Although Dan has Lab (only) mode workflows and uses Lab mode for specific parts of his "Picture Postcard Workflow" - he generally only advocates changing to another colour mode for a good reason. The good reason may be that it is quicker or easier to do something in one mode than the other or that the results are judged better by the end user when performed in one mode when compared to another.
Additionally, there are often ways that one can take advantage of the other colour mode while limiting mode conversion effects (if one is concerned) - such as using blending modes or masks and a duped copy of the original image.
Stephen Marsh
http://members.ozemail.com.au/~binaryfx/
http://prepression.blogspot.com/
http://members.ozemail.com.au/~binaryfx/
http://prepression.blogspot.com/
His specifics of quicker and easier usually boils down to your mileage may vary (he's not specific).
Quicker, easier, and without data loss is rendering the ideal pixels from raw versus fixing a turd unless that's all you have. I've said from day one, if you are presented such lemons, some of Dan's techniques do result in tastily if not overly difficult to produce lemonaid! Dan's ideas of raw processing (setting ACR sliders to zero and then fixing the resulting turd) is his M.O. Its silly but the minions buy into it for some odd reasons.
I'm presently in Quito but off to the Galapagos islands in the morning to hopefully shoot more ideal raw data to render, there's no net access so I'm not ignoring you all <g>. Please continue.
Author "Color Management for Photographers"
http://www.digitaldog.net/