Cropping for printing?

kygarden · April 1, 2006

How can I know that a crop I do will fit properly on a 4x6, 5x7 or 8x10? For example, say I want to crop out a portrait photo (vertical) out of a photo that was shot in landscape (horizontal)? What's the proper method to do the cropping so the height and width will be ok for printing?

System · April 1, 2006

do you use ps?-

if so, you have boxes in the option bar with the crop tool to type in dimensions-

george

kygarden · April 1, 2006

gefillmore wrote:

do you use ps?-

if so, you have boxes in the option bar with the crop tool to type in dimensions-

george

I don't use PS...but I could get a copy if I really needed it. For now I use Nikon Capture and Gimp for Windows.

lekke · April 1, 2006

kygarden wrote:

I don't use PS...but I could get a copy if I really needed it. For now I use Nikon Capture and Gimp for Windows.

The crop tool in Photoshop is about as simple as it gets... you click it, choose your resolution in dpi, pick the measurement units (just right click in the input boxes) and input the photo dimensions you want. Then do your selection and rotation, and the software itself will take care of resizing and resampling so you end up with what you need. Do some sharpening in the end, if needed, and you're set.

Not sure about the controls in Gimp, but resizing a photo to match your wanted dimensions isn't really that hard; i.e. say you want to print in 300dpi and you want the photo to turn out 8x10 inch. Nothing simpler: 8 inches x 300 pixels per inch = 2400 pixels needed on that axis. So, 8x10 @ 300dpi = 2400 x 3000 pixels photo.

gus · April 1, 2006

I know what your asking & for me...there is no real way of telling. I just send them off to the printer & see what happens.

My rule of thumb is not to send anything under a 1000k for a print bigger than A4 (8"x12") if that is any help. Thats about the limit i have found at 254 dpi or thereabouts.

DavidTO · April 1, 2006

kygarden wrote:

I don't use PS...but I could get a copy if I really needed it. For now I use Nikon Capture and Gimp for Windows.

Why not let smugmug do it for you when you order? You drag it, but they worry about the dimensions...

kygarden · April 1, 2006

DavidTO wrote:

Why not let smugmug do it for you when you order? You drag it, but they worry about the dimensions...

I guess the thing I was most worried about was cropping something too much so I didn't have enough of the image left to cover the entire print area. I'll try a few of the things mentioned here and see what works best for me.

kepople · April 7, 2006

must be missing something. When I do a crop, there is not an option for size.

kirby

gus · April 7, 2006

kepople wrote:

must be missing something. When I do a crop, there is not an option for size.

kirby

You can change everything in photoshop except your shoe size.

LiquidOps · April 7, 2006

Humungus wrote:

You can change everything in photoshop except your shoe size.

I hear that's coming in CS3

gus · April 7, 2006

LiquidOps wrote:

I hear that's coming in CS3

Mate i hope so...ever tried to buy 15's off the shelf :cry

LiquidOps · April 7, 2006

Humungus wrote:

Mate i hope so...ever tried to buy 15's off the shelf :cry

:tough

Jamoke · April 7, 2006

Humungus wrote:

Mate i hope so...ever tried to buy 15's off the shelf :cry

I don't know about OZ but here, finding 14's on any shelf is difficult.

Crop Size is selectable on the top toolbar... - When you have to crop tool active the toolbar shows the sizes. (K - not of shoes, but back to the crop topic) Then you click and drag...

kdog · April 7, 2006

Take your print height and width and multiply them by printer resolution. For example, say you have a pretty standard printer that prints at 300 dpi, and you want to print at 4x6.

4 x 300=1200
6 x 300 = 1800

So simply resize the picture to 1200 x 1800 pixels.

Do any cropping of the picture before you resize it. Of course you may have to play around with your cropping to match the aspect ratio of your paper size. My Canon 20D has 2x3 aspect ratio, so 4x6, and 8x12 are a no brainer, but 8x10 requires cropping.

If your prints are going to have a border, then you need to allow for that as well. So for a 4x6 with a 1/8" border, you want to resize to 3.75" x 5.75".

kepople · April 8, 2006

well, so what am I missing, can some one help me out here?
is this option only in PS Cs?

Kirby

kdog · April 8, 2006

My previous post explained how crop to a specific size for printing. It should work even with the most primitive and free image editing tools.

LuckyBob · April 9, 2006

The catch with using the resize method kdog mentioned (no offense

:) is that you're cutting detail out of the photo for no reason. Printers can still use multiple pixels for every printable pixel for in-driver color acuracy and sharpening data, plus it doesn't require saving seperate files for each print size if you plan to make more prints later.

In GIMP, there's a fairly easy way to crop a photo without altering the number of pixels in the photo. First, use the rectangular selection tool (press R on the keyboard), and in the tool's options select Fixed Aspect Ratio and type in the print size you want (the measurement units don't seem to matter in this case; somebody better with GIMP may be able to correct me). Select the area you want to print in the photo (if it's the whole photo just select from edge to edge, factoring that the aspect ratio of the camera is the same as the print), and go to Image | Crop. Then, go to Image | Print Size, and type in the print size again in the Width and Height boxes. GIMP will auto-calculate the necessary resolution for printing the crop you just specified.

It's even easier in Photoshop. Just use the crop tool and in the tool options specify a crop size. The image's resolution will be changed as soon as the crop is applied.

kepople · April 11, 2006

Is it only available on CS? PS6 does not bring up a GUI.

Thanks for the GIMP help. I will have to try that. I have that program on a Unix box, but not on my windows machine...

Kirby

kdog · April 12, 2006

LuckyBob wrote:

The catch with using the resize method kdog mentioned (no offense :) is that you're cutting detail out of the photo for no reason. Printers can still use multiple pixels for every printable pixel for in-driver color acuracy and sharpening data, ...

I guess the difference is whether you want the printer driver to down sample your image or whether you want to use a tool like Photoshop to do it. My reasoning is that I want to control the process with state-of-the-art tools, and not leave it up to the printer driver which I know nothing about. I would like to hear more about what optimizations the printer driver can do above and beyond the corrections we can do in Photoshop, if you have such information.

It's even easier in Photoshop. Just use the crop tool and in the tool options specify a crop size. The image's resolution will be changed as soon as the crop is applied.

Wait a second. The PS crop tool does PRECISELY what I described. It yields images exactly to the pixel dimensions that my formula shows. So where's the extra data in this scenario for the driver to work with?

Furthermore, if you crop at a specific size as you suggest, than you must save the cropped image at various print sizes -- something you considered to be a negative in my scenario. So in what way do you consider the PS crop tool to be different than what I described?

regards,
-joel

LuckyBob · April 13, 2006

kdog wrote:

I guess the difference is whether you want the printer driver to down sample your image or whether you want to use a tool like Photoshop to do it. My reasoning is that I want to control the process with state-of-the-art tools, and not leave it up to the printer driver which I know nothing about. I would like to hear more about what optimizations the printer driver can do above and beyond the corrections we can do in Photoshop, if you have such information.

Wait a second. The PS crop tool does PRECISELY what I described. It yields images exactly to the pixel dimensions that my formula shows. So where's the extra data in this scenario for the driver to work with? Furthermore, if you crop at a specific size as you suggest, than you must save the cropped image at various print sizes -- something you considered to be a negative in my scenario. So in what way do you consider the PS crop tool to be different than what I described?

regards,
-joel

In regards to the printer driver downscaling better than Photoshop - I concede that it's kind of a crapshoot if the driver will do better than Photoshop. My reasoning behind it is that all newer inkjet printers employ techniques such as variable droplet size, and multiple-pass printing. Also, the information I've heard has been direct from HP and Epson business reps so it might be just marketing BS; the logic seems sound to me though.

For example, Epson's newer printers are capable of eight different droplet sizes and usually make several passes over a particular point on the paper as it prints. If the print driver is told to print at 360 DPI and supplied with 360 DPI worth of data, each "pixel" on the printed page will be made up of several droplets of ink which will accurately (or at least somewhat accurately) reproduce the color it is asked to reproduce. The print head will pass over the "pixel" several times and add varying sizes of droplets of ink to create the color 1/360th inch "pixel".

On the other hand, if the printer is supplied with 1440 DPI of data and asked to print it at 360 DPI, within a single "pixel" on the printed page the printer will still make several passes using several different inks and droplet sizes to reproduce the "pixel" just as before. The difference now is the source image contains an 8x8 "grid" of actual image pixels that the printer can adjust the size and color of droplets it sprays to reproduce the color to its liking. In the below example the top right printed "pixel" could contain a small droplet concentration of black ink which would more accurately reproduce that printed "pixel" than just enough ink to recreate the overall color of the "pixel"; if you're curious I could probably figure out the math behind just how small the droplets are compared to the printer resolution's "pixel" size.

A comparison of image information versus printer's specified resolution. One square on the grid represents 1/360th".

360 DPI

1440 DPI

The end effect is that although the printer is only being asked to print at 360 DPI, the smaller droplet sizes and multiple passes have the potential of creating droplets that represent something closer to 1440 or 2880 DPI. Granted this will only theoretically increase image quality, and even if it does the quality gain would be minimal at best since the detail would be so small; the practical advantage is that you don't have to create multiple versions of the file for different print sizes.

Some further reading:
HP PhotoRET Technology: http://www.wstore.co.uk/static_uk/brandstores/hp/extras/printers_photoret/index.asp

This small drop size, combined with extremely precise algorithms, allows the cartridge to place up to 32 drops of ink on a single pixel (up to 19,200 drops of ink per inch)...

In regards to the cropping option, I forgot to mention that specifying a crop size in inches/cm (by manually typing in "6 in" for example) adjusts the photo for size and resolution; my mistake

. An example: if you've got a camera which shoots in a 3:2 aspect ratio (dSLRs), but want to print at 10in x 8in, you select the crop tool, type in "10 in" and "8 in" in the crop size boxes, and select the area of the image you want to print - this will automatically set the aspect ratio of the crop to the size you want to print, plus allow you visually to set the size of the crop without doing any math.

This method will also avoid cutting any pixel data out of the image if the source file is the same aspect ratio as the print, and you want to print the whole image. When "cropping" the image, just select the whole thing. Granted this isn't really any more effecient than just using Image | Image Resize but it does allow you to experiment with different crops of the image easily.

MyView · April 22, 2006

Ok, here's my question then. Hope I am not taking this in the wrong direction. And I'm not looking to take over the post either. Just thought this was along the same topic.

Once the photo is downsized to 4x6 at 300dpi, why when I upload it to Walmart.com to print (because I can have it in an hour) does it still crop my image. And most of the time it crops it really shitty! I swear, even if I go in there and adjust the crop that it's going to crop, it's still different once printed. And I find this a real pain in the a$$.

I know, why not let smugmug take care of the printing.

Cropping for printing?

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