Photoshop CS5 - crop to certain aspect ratio

This is probably well known to Photoshop gurus, but I had to do a lot of reverse engineering to find out how to do it in Photoshop CS5. There is probably another way.

Often, I will want to crop an image to a known aspect ratio (3:2, 4:3, 5:7, etc). I do not want any resampling done of the retained image region.

To do this, when using the crop tool, enter the aspect ratio you want in the Width and Height boxes of the tool control panel in any length unit (but not in pixels, and not without units, since in that case Photoshop will apply the unit "pixel"). Have no entry in the Resolution box. You can use inches, feet, centimeters, picas, etc.

Now, the tool will only draw a crop rectangle with the appropriate aspect ratio. When you have it in at the desired location, and of the right "scope", and commit, the image is cropped (and there is no resampling).

If you try and do this with the dimensions representing the desired aspect ratio in pixels, the aspect ratio of the crop rectangle is constrained, all right, but when you commit to the crop, the retained region is resampled to attain those pixel dimensions.

Doug_Kerr said:

This is probably well known to Photoshop gurus, but I had to do a lot of reverse engineering to find out how to do it in Photoshop CS5. There is probably another way.

Often, I will want to crop an image to a known aspect ratio (3:2, 4:3, 5:7, etc). I do not want any resampling done of the retained image region.

To do this, when using the crop tool, enter the aspect ratio you want in the Width and Height boxes of the tool control panel in any length unit (but not in pixels, and not without units, since in that case Photoshop will apply the unit "pixel"). Have no entry in the Resolution box. You can use inches, feet, centimeters, picas, etc.

Now, the tool will only draw a crop rectangle with the appropriate aspect ratio. When you have it in at the desired location, and of the right "scope", and commit, the image is cropped (and there is no resampling).

If you try and do this with the dimensions representing the desired aspect ratio in pixels, the aspect ratio of the crop rectangle is constrained, all right, but when you commit to the crop, the retained region is resampled to attain those pixel dimensions.

Click to expand...

I'm asking this from memory. What about the box for resolution with pixels/inch. If that is checked, then what.

Asher

Asher Kelman said:

I'm asking this from memory. What about the box for resolution with pixels/inch. If that is checked, then what.

Click to expand...

1. If you set Width and Height in pixels, and have nothing in the resolution box (it is a text box), the cropped image is resampled to the entered pixel dimensions (that operation is not affected by any resolution value), and the resolution indicator (meaningless) is left as is.

2. If you set Width and Height in pixels, and have a number in the resolution box, the cropped image is resampled to the entered pixel dimensions (that operation is not affected by any resolution value), and the resolution indicator (meaningless) is set to the entered resolution value.

3. [This is the case I described.] If you set Width and Height in a length unit (e.g., inches), and have nothing in the resolution box, the cropped image is not resampled. The resolution indicator (meaningless) is left as is.

4. If you set Width and Height in a length unit (e.g., inches), and have a value in the resolution box, the cropped image is resampled to the pixel dimensions which, at the entered resolution value, would correspond to the entered dimensions in inches (or whatever). The resolution indicator is set to the entered value. (It is meaningless in the future, although in this operation it controlled a conversion in image dimensions from inches to pixels to govern the resampling.)

Fascinating, wot?

Best regards,

Doug

Just a simple addenda

If you crop to 12 by 8 inches for landscape pictures, you can crop verticals to 12 by 18 inches by just adding the 1 - quick and easy for aspect ratio

Mike

Mike Shimwell said:

Just a simple addenda
If you crop to 12 by 8 inches for landscape pictures, you can crop verticals to 12 by 18 inches by just adding the 1 - quick and easy for aspect ratio

Click to expand...

Yeah, and by adding a 2 you could crop them to 12 by 28 inches... I fail to see the logic of doing that, however. 12 by 8 inches is a 4:3 aspect ratio; 18 by 12 inches is 3:2 aspect ratio. Why would you want to crop verticals 3:2 if your horizontals are 4:3?

12 by 8 is 3 to 2 ratio - consistent for both orientations. I use it to clean up quick film scans and print through Qimage, so the embedded size does not mater to me.

Of course, there is no rule that you should crop to any aspect ration at all

Mike

Mike Shimwell said:

Just a simple addenda

If you crop to 12 by 8 inches for landscape pictures, you can crop verticals to 12 by 18 inches by just adding the 1 - quick and easy for aspect ratio

Click to expand...

Or just click the "interchange Width and Height values" doodad - that's basically what it is for.

Best regards,

Doug

Mike Shimwell said:

12 by 8 is 3 to 2 ratio

Click to expand...

Oops. It must have been very late when I wrote that. ;-)

Whoa! I never noticed that doodad before... thanks!

But why after all this time does PS not have "smart" ratios like C1 does? It can tell by your mousing whether you want a horizontal or a vertical and switches automagically.

Nill

Hi, Nill,

Nill Toulme said:

Whoa! I never noticed that doodad before... thanks!

Click to expand...

Well, I find these things because I am frantically looking under every rock to find things in the PS UI that will let me work as conveniently as I can with my 2001-vintage editor!

But why after all this time does PS not have "smart" ratios like C1 does? It can tell by your mousing whether you want a horizontal or a vertical and switches automagically.

Click to expand...

Yes - Qimage does that when doing a crop to a locked aspect ratio.

It's absurd in PS that you cannot set a fixed aspect ratio for a crop in the "obvious" way: enter numbers with no units, so they can't be interpreted as "sizes", or maybe set "fixed aspect ratio" in the control panel (there's a concept).

Instead there's a secret code: enter the ratio numbers as dimensions in any unit except pixels, and don't put anything in the Resolution box. What could be more obvious!

By that time I'm just grateful that one can do it all all!

And of course there is no way to set a fixed size (in pixels) for a crop. You have to tease the mouse while watching the info screen to see what dimensions you have. And of course you can't tell where the upper-left corner of the box is unless you have the presence of mind to draw the crop box from lower left to upper right

Adobe has always been very arrogant about user interfaces. Every one of my serious applications, except any Adobe ones, allows me to customize toolbars, for example.

Best regards,

Doug

Doug_Kerr said:

It's absurd in PS that you cannot set a fixed aspect ratio for a crop in the "obvious" way: enter numbers with no units, so they can't be interpreted as "sizes", or maybe set "fixed aspect ratio" in the control panel (there's a concept).

Instead there's a secret code: enter the ratio numbers as dimensions in any unit except pixels, and don't put anything in the Resolution box. What could be more obvious!
...

Click to expand...

Well you kinda sorta can, really. For 2x3, for example, you just enter 2 tab 3. It enters the inch for you automagically. If there's a value in the resolution box you just hit tab again and delete, and you're there.

I guess you have to remember that the "inch" unit is meaningless so long as the res value is clear, although once you remember to remember that, you can forget it. ;-)

Nill

Nill Toulme said:

Well you kinda sorta can, really. For 2x3, for example, you just enter 2 tab 3. It enters the inch for you automagically. If there's a value in the resolution box you just hit tab again and delete, and you're there.

I guess you have to remember that the "inch" unit is meaningless so long as the res value is clear, although once you remember to remember that, you can forget it. ;-)

Click to expand...

Doesn't work for me. If I enter 2 tab 3 and ensure that the resolution is clear, then it assumes 2px by 3px. When I make the crop, it's only 2px by 3px.

I think you need to use the rectangular marquee tool.

Just enter a "cm" after your values instead of the "px", that should work .
However your ppi will be off after you've cropped.

You can however crop in ACR as well using a click and hold on the crop tool and enter in the aspect ratio you want to use. With this there's no need to change the ppi afterwards (if your workflow settings are set correctly that is of course).

Hi, Kevin,

Kevin Stecyk said:

I think you need to use the rectangular marquee tool.

Click to expand...

Yes, I realized that recently. I'm not sure why that escaped me before.

Curiously enough, in my most-used editor (Picture Publisher 10), there is no separate crop operation. One makes a selection (perhaps with the rectangular marquee tool, which can be set for a fixed aspect ratio) and then uses the command "crop to mask".

I have no idea why I didn't just carry that technique into Photoshop. Almost certainly it was because I didn't know that there is a "fixed aspect ratio" mode for the rectangular marquee selection tool. Its selection item is labeled "style" - who would guess that the choices (other than the default "normal") were "fixed ratio", and "fixed size"?

Thanks for your observation.

Best regards,

Doug

Hi Doug,

Actually, Jonas wins the prize for the correct answer. If you wanted a 2 x 3 crop, just enter 2 in and 3 in while leaving the resolution blank. Or use 2 cm by 3 cm while leaving the resolution blank.

Our mistake was leaving everything blank and Photoshop seemed to believe we wanted pixels.

The advantage of the Crop Tool as opposed to the Marquee tool is that your rule of thirds follows you along.

Kevin

Hi, Kevin,

Kevin Stecyk said:

Hi Doug,

Actually, Jonas wins the prize for the correct answer. If you wanted a 2 x 3 crop, just enter 2 in and 3 in while leaving the resolution blank. Or use 2 cm by 3 cm while leaving the resolution blank.

Click to expand...

Yes, as I had noted in my original May, 2010 post on this matter:

The advantage of the Crop Tool as opposed to the Marquee tool is that your rule of thirds follows you along.

Click to expand...

Good point. Thanks.

Best regards,

Doug

This may or may not be relevant but it's easier in Lightroom. After you click on the crop tool, you just click on the dropdown besides the Lock/Unlock icon. That gives you a choice of aspect ratios, or you can define your own which will then appear in that list.