Using the crop tool to crop to pixel dimensions is not possible.
The crop tool will only let you set the aspect ratio, so you have to figure out the aspect ratio, and enter it.
Then export the image with the pixel dimensions you need.
so you have to figure out the aspect ratio, and enter it
Actually, you can just enter the pixel dimension in the custom dialog.
It will create the correct aspect ratio, but not crop to the pixel dimensions,
And the pixel dimensions listed in the screenshot above are just examples of common dimensions for the aspect ratios.
Per, thanks for your response. I believe you are right that LR does not have this capability, but I am hoping someone has found a way.
As you are probably aware, Lightroom is a nondestructive editing program. You cannot trim pixels from a master image in Lightroom. The process is to crop to the appropriate aspect ratio. Lightroom retains all of the pixels of the original image, but will display the image in the desired aspect ratio after you crop. The export dialogue is then used to export a copy of the image which has the number of pixels that you need. There is no way to "figure out" another way to do it. If you must have the image cropped to a specific number of pixels you will have to do it in Photoshop or some other pixel editing program. But what ever work you do in Photoshop will be returned to Lightroom as a copy of the original image.
Thanks Jim. You are right; I am aware the LR is a nondestructive editor. I do not want to destroy any pixels.
There is a way to do this in LR, which is the way I do it now. The problem is that it is too difficult and time consuming. Today I set the aspect ratio I want and then keep adjusting the crop, using the mouse or Wacom, until it has exactly the number of pixels I want. This method works but it is extremely difficult to get the number of pixels exactly right. My manual dexterity with a mouse or stylus is just not good enough! Many iterations of the crop are required and sometimes I cannot get it just right.
If it were possible to expand or shrink the crop one pixel at a time to adjust the crop very precisely that would be a big improvement. For example, if there were a key sequence that incremented or decremented the number of pixels on the long axis of a crop that would work, but there does not seem to be such a key sequence. Maybe someone has written or could write a plugin to allow more precise control over cropping. I know that Adobe severely limits what can be done in plugins so maybe that is not possible.
Why? Are you really adjusting an image based on number of pixels rather than on composition?
keep adjusting the crop, using the mouse or Wacom, until it has exactly the number of pixels I want.
I don't understand how you can do that.
In any case, you're making this a lot harder than it is.
Simply enter the pixel dimensions in the Custom crop dialog in Develop. Now this custom setting, which gives you the correct proportions but not the pixel dimensions, will be available every time you go into that dialog.
If you like, you can apply the crop to a virtual copy, that will sit next to the original in the Library.
Whatever you do, you have to enter the pixel dimensions (long side or short side will be enough) when you export the image.
Alternatively. choose Edit in Photoshop and crop the image there, or export the whole image and crop in PS.
As JimHess has told you, LR is not a pixel editor - it never touches the original image. All your adjustments are saved to the catalog, and is only applied to a copy of the image when you export or print.
Just to clarify, you are not modifying the size of the image when you adjust the crop. All you are changing is the number of pixels that are being displayed. If you were somehow able to set the crop to the precise number of pixels that you want, and then simply handed the image to someone else, the size that you crop it to would be gone. You really should rethink your workflow and consider exporting a copy. That copy can be sized properly in the export dialogue.
Joe, when normally processing photos I do what you and others do which is to crop to a specific aspect ratio based on image content. That is not always the case. For example, to do some imaging system analysis it is important that pixel data not be altered and that pixel data be exactly comparable. Sometimes that means that the image samples need to be a particular size. If they are made the same size by using the LR export module the original data is resampled, a destructive process.
Per, I adjust the crop size the usual way. I use the mouse or the Wacom stylus to grab a corner of the crop and drag it while watching the crop dimensions. Getting it close is easy. Getting it exact is tedious. I have a few thousand samples I want to take so I am looking for an easier method. You have suggested a couple of times that the solution is to use the export module to adjust the size. The problem is that if the image size is changed the image data is resampled which alters the pixel data and different samples do not overlay properly. Most of the time the slight loss of image information is not an issue but in this case it is.
So, just to be clear, you are trying to crop the master image to exact pixel dimensions. And then you are handing that cropped master image to someone else. Is that correct?
How can you see the pixel dimensions when adjusting the crop in Lightroom? I don't think that's possible.
It's sound like you're doing this in Photoshop, where you can indeed see the dimensions.
The problem is that if the image size is changed the image data is resampled
Well if you want specific pixel dimensions, the image will most likely be resampled, depending on the pixel dimensions of the original.
If resampling is not acceptable, you would have to export the image with Resize to fit unchecked, or use Edit in Photoshop, after having set a crop with the correct aspect ratio in LR.
May be I'm missing something here, but you seem to want to crop to specific pixel dimensions without resampling, which in most cases would be impossible.
For example, to do some imaging system analysis it is important that pixel data not be altered and that pixel data be exactly comparable. Sometimes that means that the image samples need to be a particular size. If they are made the same size by using the LR export module the original data is resampled, a destructive process.
As Per Berntsen suggested you can use the Crop Overlay tool by entering the desired pixel dimensions into the 'Enter Custom' option. Unfortunately it only uses two decimal place precision, which is probably not accurate enough for your application.
Photoshop's Crop tool allows entering the crop dimensions in pixels, which is what you need. Select Style> 'Fixed size' and enter the specific crop dimensions you want as shown in the example below for 5000 x 3744. You'll still need to center the crop on the image manually, but it will retain the exact pixel dimensions. You can also use a PS Action for batch processing multiple images.
Jim, thanks for the clarification. As I mentioned, we are well aware of how PS and LR operate on the data and how to exchange image samples. FYI, we have been using PS since it was known as "Barneyscan".
Thanks to you, Per and Joe for taking the time to reply to my post. I will probably write a PS action to automate this task.
Thanks for your note. As you suggest a PS action is the way to go. I have a lot of images and will need to batch them as you suggest.