Color correction help needed......I'm color blind.

Tom K.

I am color blind. I can see color but can't differentiate between reds, greens, browns when they are all mixed up.

Can you point me to a color correction method that is a "by the numbers" technique that does not depend on one's ability to see color. I am currently testing two methods and am looking for more methods and techniques to find the perfect one that will solve this colorblind condition.

I should be receiving this book very, very soon and I am sure that will help. Right now I am looking for any OTHER techniques that use a "by the numbers" methodology.

Thank you very much.

rutt

Of course, there is Dan's other book, Professional Photoshop in which he claims he can teach a color blind gorilla to color correct. One book of Dan's at a time might be enough, though, and I think the one you ordered is easier. At least the first 7 chapters. But Professional Photoshop might address your needs more directly.

Dan is Mr. By-The-Numbers color correction and there is no By-The-Numbers color corrector before him. The others will tell you to calibrate your monitor.

pathfinder

Nothing wrong with a calibrated monitor. :uhoh

I'll bet Mr Margulis uses a carefully calibrated monitor. Just don'e believe your eyes and the monitor!! - look at the numbers, esp, those for white, black,and greys. : : And then the reds, and blues, and cyans, etc.

The first half of Professional Photoshop might be more help for a beginner than The Canyon conundrum, don't you think John??

Tom K.

I'm not a beginner. I have been using Photoshop for years.....but......the color blind thing could be solved with a "by the numbers approach". I'll take your advice and learn one book at a time.

I have been using a method by Katrin Eismann which features marking black, white and grey areas of an image and then using the info pallet to make the R B and G numbers equal out. It's not perfect but it does produce very good results in many photos. (I think )


Thanks for the advice.

rutt

pathfinder wrote:

Nothing wrong with a calibrated monitor. :uhoh

I'll bet Mr Margulis uses a carefully calibrated monitor. Just don'e believe your eyes and the monitor!! - look at the numbers, esp, those for white, black,and greys. : : And then the reds, and blues, and cyans, etc.

The first half of Professional Photoshop might be more help for a beginner than The Canyon conundrum, don't you think John??

Let's see. Calibrated monitors. Dan is fussy but doesn't use calibration hardware. You know the drill. Make the background and the apple look as much alike as possible.

But Dan did make us correct color with our monitors in gray scale mode.

I think Professional Photoshop might be more helpful to someone who is color blind, but LAB Color is easier. Pull in the ends of the curves and bingo it looks better. That's what made it a best seller.

edgework

Tom K. wrote:

I'm not a beginner. I have been using Photoshop for years.....but......the color blind thing could be solved with a "by the numbers approach". I'll take your advice and learn one book at a time.

I have been using a method by Katrin Eismann which features marking black, white and grey areas of an image and then using the info pallet to make the R B and G numbers equal out. It's not perfect but it does produce very good results in many photos. (I think )


Thanks for the advice.

Eismann's approach is simple logic: any irregularities affecting the neutral areas are going to be affecting the rest of the image as well. We might not know how "Red" that apple should be, or how "Blue" those jeans are, but if you have something that's neutral, there's not a lot of room for argument.

But it's easier in LAB, because you needn't worry about lightening and darkening as you're trying to bring your colors into sync.

The method I use isn't spelled out in Dan's latest book; I picked it up in an earlier edition of Professional Photoshop, but it uses the same by-the-numbers logic.

Set a curve adjustment layer.

When you open the curves window, make sure that the gradient is set for blacks to the left, whites to the right. This matches the curve values to the Info readout.

Plant some Info samplers: preferably on highlight areas but any neutrals will work. It's just that casts in shadows don't affect an image as drastically as in highlights.

Read the values for A and B. Neutral is always A=0, B=0. Any deviation is a precise measure of the cast. Say, for example, you see A=3, B= -6. You know you have a bluish cast.

Set an anchor point in the middle of each channel's curve. Plug the readout value into the Input box, and set the output box to 0. in this case, for your A curve, you would put 3 in the input, and for the B curve you would put -6.

No more cast.

The beautiful thing about it is you don't have to think about it. The numbers cannot lie, and in LAB, they're more precise, with less potential for damage.

If, as is often the case, you set two or three samplers, and you have different values in each, start with the lightest values first and eliminate the cast in that region.

If your mid tone or shadow samplers are still showing a cast, set a second curve adjustment layer and repeat the process. However, since you've already handled the highlights, you'll want to go into your blending options window and use your blending sliders to restrict the scope of this second curve to midtones and shadows. You can simply watch your Info palette to see where the sliders need to be set. As soon as you've stopped affecting the highlight values (meaning they've returned to 0,0), that's where your sliders should beging taking affect.

(If you're not sure about blending sliders, check out Chapter 8 of Dan's LAB book, where he discusses them in great detail. Rutt has a nicely detailed summary here.

I've sometimes used as many as four different curves, targeted to different ranges, to totally remove a cast. It's always worked. And then I can get on with the business off working on contrast, sharpening and enhancing the colors that now are cast free.

Once my cast issues are handled, I'll forget about those curves, and start above them with a fresh adjustment layer for any contrast moves to the lightness channel or any color enhancements to the A and B channels.

rutt

Pay attention to Edgework. You won't get any better advice here.

pathfinder

Tom K. wrote:

I'm not a beginner. I have been using Photoshop for years.....but......the color blind thing could be solved with a "by the numbers approach". I'll take your advice and learn one book at a time.

I have been using a method by Katrin Eismann which features marking black, white and grey areas of an image and then using the info pallet to make the R B and G numbers equal out. It's not perfect but it does produce very good results in many photos. (I think )


Thanks for the advice.

My mistake Tom. I made an assumption that was incorrect. Sorry again

Tom K.

Many thanks for those words of wisdom. I will now retreat to Photoshop CS2 for a go at it. What you have described is very exciting to me. This could be the answer I have been looking for.

Note to self: "Do not have Amazon.com ship anything for free.....it takes WAAAAAY too long for delivery". Thus...I have yet to receive THE book.

Tom K.

pathfinder wrote:

My mistake Tom. I made an assumption that was incorrect. Sorry again

No need to apologize. My lack of info made your assumption a rational one.

This is one great forum.........WHY?????.......it's because of the wonderfully helpful and generous people that visit here. I'm lucky I found Dgrin.

Tom K.

edgework wrote:

If your mid tone or shadow samplers are still showing a cast, set a second curve adjustment layer and repeat the process. However, since you've already handled the highlights, you'll want to go into your blending options window and use your blending sliders to restrict the scope of this second curve to midtones and shadows. You can simply watch your Info palette to see where the sliders need to be set. As soon as you've stopped affecting the highlight values (meaning they've returned to 0,0), that's where your sliders should beging taking affect.

(If you're not sure about blending sliders, check out Chapter 8 of Dan's LAB book, where he discusses them in great detail. Rutt has a nicely detailed summary here.

I've sometimes used as many as four different curves, targeted to different ranges, to totally remove a cast. It's always worked. And then I can get on with the business off working on contrast, sharpening and enhancing the colors that now are cast free.

Once my cast issues are handled, I'll forget about those curves, and start above them with a fresh adjustment layer for any contrast moves to the lightness channel or any color enhancements to the A and B channels.

So far I am extremely happy with the method you have layed out. In fact when I applied this technique to the first few images I tested it on I nearly jumped out of my seat when I punched in the last number in the b channel. W0W!!! This is superb for the my color blind challenged eyeballs. I can't thank you enough.

I attempted to add another curve layer and then use the blending option but for some odd reason the info pallet did not respond at all. No change in numbers in the info pallet while adjusting the blending sliders. It must be some thing I am overlooking. Once I get that figured out then my color blind problem will be a thing of the past (with regards to color cast removal).

Many thanks for the brilliant advice. You made my day.

edgework

Tom K. wrote:

So far I am extremely happy with the method you have layed out. In fact when I applied this technique to the first few images I tested it on I nearly jumped out of my seat when I punched in the last number in the b channel. W0W!!! This is superb for the my color blind challenged eyeballs. I can't thank you enough.

I attempted to add another curve layer and then use the blending option but for some odd reason the info pallet did not respond at all. No change in numbers in the info pallet while adjusting the blending sliders. It must be some thing I am overlooking. Once I get that figured out then my color blind problem will be a thing of the past (with regards to color cast removal).

Many thanks for the brilliant advice. You made my day.

I don't have image samples yet (working on them as part of a larger workflow demonstration), but here's how it should go down:

This will be the initial step in your work flow so we'll assume you have three layers, the initial image and two curves. You have two Info samplers set, one on highlights and one on shadows. You've already set your highlights so the readout on the palette should be A=0, B=0. And we'll assume there are still cast values showing for your shadow sampler.

Now set the values for your shadow curve. Close the curve dialogue. You should see the precise inverse of the previous readings. In other words, if your highlight readout had been A=0, B=0 and your shadow was reading A=2, B= -3, after setting values in your shadow curve, your readout should be reversed. Highlights will read A= -2, B=3, and Shadow will read A=0, B=0.

With the shadow curve layer active, double-click to the right of the layer name. The Blending Options dialogue will come up. Your Info Palette will show two sets of values for each sampler, a before and after. It's the "after" values that you want to pay attention to.

Click and drag the dual white anchors to the left. Release and see if the readout changes. Keep doing that until the "after" values revert to 0,0. Push back the other way until you find the exact point where the shadow curve is no longer affecting the highlight sampler readout.

Now Option-Click on the left half of the white anchors to split them and drag that half-anchor a bit further to the left, to smooth out the transition.

When you close the dialogue, you should see 0,0 in the A and B values for both your Info samplers.

Tom K.

I must say edgework you are a fine teacher (superb in fact). These instructions were easy to follow and a pleasure to work with. I applied the technique and it worked flawlessly. This is absolutely wonderful for me and eliminates my color blind problem with regards to removing a color cast.

I can't thank you enough.

rutt

Actually, this is a great and very methodical approach to this problem. I had the pieces ala Chapter 7, but Edgework's approach is cleaner and more general. From what he said to me, I think Dan still thinks that RGB or CMYK curves are the best approach to this sort of mixed cast.

Nice.

Tom K.

rutt wrote:

Actually, this is a great and very methodical approach to this problem. I had the pieces ala Chapter 7, but Edgework's approach is cleaner and more general. From what he said to me, I think Dan still thinks that RGB or CMYK curves are the best approach to this sort of mixed cast.

Nice.

I have used the RGB method ala Katrin Eismann. The CMYK method would be one that I would like to try. Does it follow along the same lines as the Eismann technique?

Tom K.

I came across this link. May be useful for other colorblind individuals: http://www.nicholsonprints.com/Articles/colorblind.htm