Why won't my PSD file resave at 85% size, higher res jpeg?

[Sandilou]

Hi – I have a psd 300ppi image at 19.3 x 12.9 that I want to have printed at 85% actual. I resized the image to 85%. Image is now 350ppi at 16.4 x 10.9" and I save as a jpeg (maximum quality). All good. Just before I send to the printer, I opened up the file to check the size and it's reverted back to 300ppi, 19.3 x 12.9. 

Why won't it save at the 85% size, 350ppi.  I tried to save as a tif using the same procedure as above and get the same result.

Thanks in advance. Sandra

[Sandilou]

Extra info – I'm using Photoshop 22.5.5. 

[TheDigitalDog]

What are the original pixel dimensions (HxW) and the newer (resized) pixel dimensions (HxW)? That's what counts.

[D Fosse]

Those numbers don't really make sense.

19.3 x 12.9 at 300 ppi = 5790 x 3860 pixels.

16.4 x 10.9 at 350 ppi = 5740 x 3827 pixels.

So that's a very tiny amount of downsampling and one could ask what the purpose is? It's virtually the same file. It would be better to uncheck resample and just set the desired print size. The ppi would then come out as 353.

To be clear: the ppi number is just metadata. It doesn't change the file, it just defines the pixel density on paper and hence the reproduction size.

Ppi can be used to calculate resampling, but there's no need for that here.

Oh, and to answer the question: As long as this is set in Image Size in Photoshop, I can't think of any reason why it shouldn't stick - unless the metadata is stripped from the file. But then it should default to 72 in Photoshop.

[Sandilou]

Hi. Thanks for responding.

I'm attaching the Image Size box.

First image is the original size of the psd file. 

Second image is the resized file size at 85%. I save this file as a jpeg.

Third image is the jpeg, opened up at poof! Same size as the original.

I guess my dilema is the print company wants the file saved at whatever output size I want. I know it's only an extra 50px per inch, but I wanted to squeeze as much resolution out of the file as I could. I supposed it's not necessary. It's just baffling it does this.

Sandra

[Sandilou]

And, here is the 3rd image again, except with inches shown instead of percent. Baffling to me. I must have ticked a box somewhere.

[TheDigitalDog · Accepted solution]

The problem is, you are NOT altering the number of pixels. You are simply changing the resolution metadata tag which is basically useless. Work in Pixels IF indeed, you wish to reduce the 'size' of the image itself.

Maybe a resolution primer will help here. Old but nothing has changed in all the years since written.

http://digitaldog.net/files/Resolution.pdf

[Sandilou]

And it works! As you have said. Thank you for this. 

I do appreciate the support community and especially those who reach out to help.

Sandra

[D Fosse]

OK, so no resampling, just inaccurate numbers in the first post. The file is still 5799 x 3866 pixels, so nothing really changed and the file isn't really "resized", it just has new ppi metadata.

But as I said, I can't think of any reason this new ppi number shouldn't be saved with the file. I've never seen or heard of that happening.

Does this still happen with other files? Could it be that you hit Cancel instead of OK? Not implying anything, just have to ask...

[Sandilou]

No. I've resaved it a few times just to make sure. I've unchecked the "resample" box and saved the file down to 85%, which works. I suppose a few pixels here or there won't make or break the image. 

Thanks for your help. Sandra

[D Fosse]

Actually it's not "a few pixels here or there". It's exactly the same file. It hasn't changed at all! It's important that you understand this.

Pixels per inch, ppi, is probably the most misunderstood concept in all of digital imaging. It's not a file property. It becomes much easier to understand if you read it literally, word for word. It means exactly what it says: pixels per inch.

It's just a standard equation. If ppi goes up, size goes down, and vice versa. It doesn't change a single pixel.