Photoshop crop creates blurry images?

Ged

Ive just been trying to crop a series of pngs(animation), there are about 400 frames so I created a photoshop batch process to take the canvas size from 569x320 to 512x320 but when I compare the output images to the input images there is very noticable blur! this is really wierd as I thought the image would not be resampled.

When I tried using canvas to crop within photoshop the blurring did not occur

this is photoshop CS5, anyone got a solution?

Mark Dygert

Do you want to crop the images and get rid of a few pixels? Or squash it down and resize them using something like Main Menu > Image > Image Size?

The Crop Tool shouldn't resample unless you specify a height width or resolution, then I don't think it has any options for what sampling method to use. So if you're going to crop you might want to clear those boxes and set out guides where you want to crop (possible action?) and do it with those boxes clear.


Image Size has a "Resample Image" check box with a few options that help control what it does to the pixels. "Nearest Neighbor" is probably your best bet for per-pixel stuff but because its squashed its going to be messy.


You can record an action of yourself cropping one image using the Crop command instead of the tool and then use batch to apply that to all of the images of that size

Measure out the space you want to crop, lay down some guides.
Start recording
Marque select the area
Go Image > Crop
Save
Stop recording
Batch that action on a folder and go get some coffee.

Ged

Vig wrote: »

Measure out the space you want to crop, lay down some guides.
Start recording
Marque select the area
Go Image > Crop
Save
Stop recording
Batch that action on a folder and go get some coffee.

thanks vig might give this a go tomorrow, yeah crop(canvas size) really shouldnt resample or blur an image at all but when I ran a canvas size action on a folder it blurred all of the images. Your method of doing it with a selection sounds like it might work but really this must be a flaw/bug in photoshop.

Ged

it works! thanks alot, dont really understand why canvas size makes things blurry but I wont use it in that way again

Mark Dygert

Yea there are a lot of pieces of photoshop that leave me scratching my head. Glad it worked!

kodde

You didn't actually type in your new dimensions in the type in field at the top with the crop tool? That is a resize action and would explain the behavior.

Ged

kodde wrote: »

You didn't actually type in your new dimensions in the type in field at the top with the crop tool? That is a resize action and would explain the behavior.

nope I was using canvas size to crop at the beginning but it seems canvas size does not actually physically crop but slightly resamples but it only does this when used on a batch process, it doesnt blur/resample at all when used in photoshop on a single image.

kodde

That's way weird. Good to hear that it worked out well anyways.