Cropping to Aspect Ratio- slightly off

StudioVoxPop

Hi there--

I'm trying to crop a bunch of photos to a specific aspect ratio in Photoshop CS2. I'm using the marquee tool and entering in the fixed aspect ratio. However, about 70% of the time, when I drag a rectangle around the part of the image I wish to keep and then select image - crop, the measurememnts are just slightly off what they should be for the selected aspect ratio.

For example-- I'll open a file and put my aspect ratio as Width 1.5 to Height 1. I'll drag over my image and select crop. However, when I go to resize the image to a format that should work in a 1.5 to 1 aspect ration (like 36in X 24in), I end up with an image that's 36.015in X 24in or something similar.

So then I have to back track, drag the marquee again and, eventually, it does crop correctly and I can get the 36in X 24in photo I need.

It's very frustrating as I have a lot of photos to crop and I need the aspect ratio to be spot on. :bash

Any thoughts out there?

LuckyBob

I havn't had near as much of a problem just setting the final image size in the crop options. If you just type in "36in" and "24in", it shouldn't be more than around 1/100" off in my experience, and I'd be willing to bet that the margin of error would be just about one pixel size.

StudioVoxPop

LuckyBob wrote:

I havn't had near as much of a problem just setting the final image size in the crop options. If you just type in "36in" and "24in", it shouldn't be more than around 1/100" off in my experience, and I'd be willing to bet that the margin of error would be just about one pixel size.

The problem is that I'm not really trying to resize. I'm taking my photos and cropping them to a 1.5:1 aspect ratio while trying to keep them as close to the original size as possible. That's why I'm using the marquee tool. If I was resizing, I would blow the original up and then use the crop tool (with actual measurements).

jfriend

StudioVoxPop wrote:

The problem is that I'm not really trying to resize. I'm taking my photos and cropping them to a 1.5:1 aspect ratio while trying to keep them as close to the original size as possible. That's why I'm using the marquee tool. If I was resizing, I would blow the original up and then use the crop tool (with actual measurements).

You can use the crop tool without any resizing/resampling. In CS2, enter the dimensions you want and just make sure that the resolution box is empty. That will resize to the aspect ratio you select and label the image with the dimensions you put into the crop tool, but NOT resize or resample it at all. I do this all the time for crop without resample.

StudioVoxPop

jfriend wrote:

You can use the crop tool without any resizing/resampling. In CS2, enter the dimensions you want and just make sure that the resolution box is empty. That will resize to the aspect ratio you select and label the image with the dimensions you put into the crop tool, but NOT resize or resample it at all. I do this all the time for crop without resample.

Thanks for the idea...

The problem is that I need to crop to a specific aspect ratio while keeping the image as close to the original size as possible. So, unless I do some tricky math, I don't know what the new dimentions need to be to get it to the correct aspect ratio. I'm also cropping a bunch of photos here and they all vary in size so doing tricky math on all of them isn't practical.

jfriend

StudioVoxPop wrote:

Thanks for the idea...

The problem is that I need to crop to a specific aspect ratio while keeping the image as close to the original size as possible. So, unless I do some tricky math, I don't know what the new dimentions need to be to get it to the correct aspect ratio. I'm also cropping a bunch of photos here and they all vary in size so doing tricky math on all of them isn't practical.

No tricky math required. You said in an earlier posting that you want a 1.5:1 crop ratio. Select the crop tool. Enter dimensions of 15" and 10" and clear the resolution field. The crop tool will now be fixed at a 1.5:1 crop ratio, but you can drag a corner to the exact size you want over your picture, cropping as little or as much as you want for the desired shot. Try it. It will work great for what you've described you are trying to do. If you come to an image with a different orientation, just click on the two arrows between the 15 and 10 and it will swap them changing the orientation of the crop area.

Mission accomplished. No math required.

The crop tool in CSx is a very confusing tool because, depending upon how you use it, it can produce a bunch of different effects.

With the width and height filled in and the resolution field blank, it crops to a specific aspect ratio without resampling. It also changes the "document size" stamped on the image (similar to the Image/Image Size dialog with resample image unchecked) which confuses the hell out of people, but has very little impact on anything as long as you tell your printer what output image size you want.

With the width, height and resoltion fields all filled in, it crops to a specific aspect ratio and resamples the image which is bizarre to me for a crop tool. It seems that a crop tool should crop, not resample too. I NEVER use the resolution field in the crop tool. If I want to resample, I use the Image/Image Size dialog and explicitly resample there.

After all this discussion of using the crop tool to crop, but NOT resize, from your original message, it sounds like you are actually trying to do both, but in two steps. Why not just do it in one step with the crop tool. If you want to end up with an image that is exactly 24" x 36" and 240 dpi, then just enter those values into the crop tool, pick your crop area and you will have your desired result with no slight error. It will be a 1.5:1 aspect ratio. It will be labeled as 24" x 36" and it will have been resized to be 5760x8640 pixels (which is 240dpi at 24"x36").

Starting in a few hours, I'll be offline for awhile so if you want to continue this discussion, hopefully someone else can chime in.