Crop tool: How to crop to a specific size?

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kevinm

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When using the crop tool, I can't figure out how to crop to a specific size, e.g. so that the longest side of a given image is, say, 1'24. I'm sure it must be feasible... Thanks in advance.
 
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the crop tool only crops to a proportion. The image size is done at export. You select the longest edge as the dimension in the export dialogue box and put the pixels in there.
 
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This is done at export mainly.

In develop you can choose the aspect ratio 1:1, 8x1', original or custom...what ever is required. When you want to export choose the specific restriction you have to constrain to, longest edge etc.
 
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It can be done but its hit and miss. In the develop mode make sure the "cropped dimensions" is included in the view>view options. Press R to get the crop mode. Select the crop aspect ratio you require and make sure it is constrained. Then drag on the corner of the box to change the pixel size of the crop. You have to drag it a little bit and then let go so that the "crop dimensions" updates itself...then drag it a bit more etc. until to get to the required pixel size. You will get it fairly close pretty quickly but good luck in getting to the exact pixel size. You need a good mouse and a steady hand !! Once at the required pixel size you can drag the crop box to where you want it.
 
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Mark I don't think that is what Kevin wants. What you are saying will not reduce the image but crop it to a pixel size. I would guess that Kevin wants to reduce the image down to a particular size.
Brad, you said it better than i did
 
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[quote author=Andrew Hayton link=topic=7478.msg51157#msg51157 date=124961191']
Mark I don't think that is what Kevin wants. What you are saying will not reduce the image but crop it to a pixel size. I would guess that Kevin wants to reduce the image down to a particular size.
Brad, you said it better than i did
[/quote]

You are probably right but then again he was referring to "cropping" the image using the crop tool ? At least all his options are now covered. Incidently using the method I described I was only able to get within 2px of a target size.
 
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thats not bad going Mark
 
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Now I'm confused...

In development Module, I select crop at say 6x4 as the pictures will be printed on a 6x4 paper. When I export, I leave the 'Image Sizing' section unchecked. I send those exported files to print at a lab for 6x4 and all is good.
Rgds
 
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Patrick, what you are doing is correct in the develop module as you want a 6x4 aspect ratio crop, but when you come to export, you are exporting the files at full size which is not a problem but you are creating big files which are not necessary. What you can do is set the export dimensions as 6inch x 4 inch and 3''dpi. This will create smaller files and i think your lab would be happier as they will process quicker
 
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The disadvantage to not resizing on export, other than the unnecessarily large file, is that you're not taking full advantage of Lightroom's export sharpening. LR's export sharpening is optimized for sharpening at the final size. You're sharpening and then letting your printer resize, so you're resizing after sharpening.
 
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As others have already pointed out, this is one of the defencies in LR. Unlike Photoshop or any other imaging program that I've used, you can not in advance dictate the length of a crop edge in Pixels You can Crop to a ratio (many of the predefined patterns are the same ratio BTW). If you create a custom ratio 4X3, you will have the same proportions as 1'24X768 Knowing the pixel size of the original, you can estimate approximately what part of the image width you need to crop ot 1'24 pixels. Once you are close, save the crop as a snapshot.
You can alter the dimensions of your crop to some specific value by altering the parameters of a Snaphot outside of lightroom using an EXIF editor that will write to the XMP after lightroom has written them to the Snapshot section of the XMP file or XMP portion of the EXIF.

Putting in a feature request might help get this simple common crop method introduced in some future version of Lightroom.
 
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you can set the crop ratio to 1'24x768 in the crop tool and save it as a custom crop
 
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[quote author=Andrew Hayton link=topic=7478.msg5117'#msg5117' date=1249615532]
you can set the crop ratio to 1'24x768 in the crop tool and save it as a custom crop
[/quote]The largest value accepted by the custom crop dialog box is 999.999 And even if you could enter the 1'24 value it would still be a ratio of 4:3 and not a finite pixel dimension.
 
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but that is the idea of the crop tool, perhaps it should be renamed ratio tool as the pixel dimension is set on export
 
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[quote author=Andrew Hayton link=topic=7478.msg51174#msg51174 date=1249616'22]
but that is the idea of the crop tool, perhaps it should be renamed ratio tool as the pixel dimension is set on export
[/quote]The Pixel dimension is set (at least as a percentage of the full image pixel dimension) in the Snapshot metadata in the XMP or the catalog. What happens at export is a resize function where each output pixel is derived from parts of the filtered original pixels in the vicinity of the output pixel. (i.e. if your original pixels on an edge is 1'78 and your output is 1'24, the each output pixel will represent 1.'527344 of the original pixels) If I want to print an 8X1' at 3''dpi wouldn't it be better to start with an image that is 24''X3'''px than one that is 2543X3178px? You have to leave Lightroom and go to Photoshop to do that.
 
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[quote author=Mark Sirota link=topic=7478.msg51168#msg51168 date=1249614895]
The disadvantage to not resizing on export, other than the unnecessarily large file, is that you're not taking full advantage of Lightroom's export sharpening. LR's export sharpening is optimized for sharpening at the final size. You're sharpening and then letting your printer resize, so you're resizing after sharpening.
[/quote]

On export, I too also select the Output Sharpenign section. Isn't this export sharpening already?
 
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Thanks everyone.
Actually what MarkNicholas described is what I wanted as I do want to crop to a specific pixel size although a few pixels one side or another is no big deal; so his methods works well, although of course it is a little clunky (thanks to LR and not to Mark).
The reason I want to do this is that I need to provide some images that will be projected and the maximum longest-dimension size is 1'24. My Canon 5DII produces huge files, and I am a keen-cropper, so I want to do some major cropping, while still knowing that I am not cropping to anything smaller than the required 1'24. Hope this makes sense...
 
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[quote author=Souwalker link=topic=7478.msg5118'#msg5118' date=1249625622]
On export, I too also select the Output Sharpenign section. Isn't this export sharpening already?[/quote]
Same thing. The output (export) sharpening is being applied to the full-resolution file, then your printer is downsizing it. If you resize on export, then it'll resize and then sharpen, for better sharpening results.

It's also likely that Lightroom can do a better job of resizing, because it has access to the raw data and can resize in linear space (before gamma correction). Your printer can't do that.
 
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[quote author=kevinm link=topic=7478.msg51188#msg51188 date=1249646871]
Thanks everyone.
Actually what MarkNicholas described is what I wanted as I do want to crop to a specific pixel size although a few pixels one side or another is no big deal; so his methods works well, although of course it is a little clunky (thanks to LR and not to Mark).
The reason I want to do this is that I need to provide some images that will be projected and the maximum longest-dimension size is 1'24. My Canon 5DII produces huge files, and I am a keen-cropper, so I want to do some major cropping, while still knowing that I am not cropping to anything smaller than the required 1'24. Hope this makes sense...
[/quote]

Glad to be of help...It looks like the others have decided to talk about something else
 
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