Edit each page of a multi-page PDF document without any data loss/downsampling

[Tommy J.]

I have a 68-page PDF file and I need to adjust each page seperately in PS in order to straighten them out, but it is importand to do so without any data loss or downsampling in the process.

I've tried to open the PDF in PS and then save each page in uncompressed/undownsampled TIFF file after editng it but after carefully inspecting the TIFF file I noticed that it looks slightly more sharp than the original image in the PDF. I've also tried to export each page from Acrobat in JP2 but they look slightly more blury if you compare them with the PDF. I've even tried opening a specific page in PS and then saving through Automate > PDF Presentation but it's also not the same if you zoom real close and compare the original PDF file with the the new PDF. No matter what I do it's never exactly the same.

Is there a method through which I could do that with absolutely no quality loss in the editting process?

[Test Screen Name]

Straightening a bitmap is a massive rearrangement of pixels, essentially like downsampling. You pick up the pixels and drop them on a different pixel grid. Also, even opening a PDF in Photoshop forces a rasterisation at a resoution you arbitrarily chose. Maybe you can find a tool to do free rotation in Acrobat, without rasterising.

[Mylenium]

There's always going to be re-sampling, no matter the method. Even PDF-editing tools rasterize transformed objects. What you want is simply technically impossible.

Mylenium

[Stephen_A_Marsh]

You should have the option to open the PDF images in the file (at their original resolution), rather than opening and rasterizing the actual page. This is at the head of the window where you pick your pages, select the image option instead.

PDF files could contain images; text and vector data on each page. This is why there is a feature to extract the images. So if this multi page PDF has one image per page then that would result in the same count of images as pages, but you would be using the images native pixels, not a rasterization of a raster at a different pixel size/resolution. Hope this makes sense.

[Tommy J.]

Thank you for your helpful reply Mr Stephen_A_Marsh! It definitely makes sence.

After I've opened this way each page/image of the PDF and edited it, could you please tell me your opinion on how I should proceed in order to avoid any possible downsampling? I know that the pages of the document were initially scanned in 600 DPI, saved in JP2 files and then merged in a single PDF file through Acrobat. Now I need to edit them one by one in PS and create a new PDF file. My main concern though is to do so without compromising to the least bit the quality of the original images. Would that be technically possible? 

[jane-e]

I have a 68-page PDF file and I need to adjust each page seperately in PS in order to straighten them out...Is there a method through which I could do that with absolutely no quality loss in the editting process?

Hi

In Acrobat, use the Export PDF toolbar and either export each page to a tiff or click the checkbox to export all images to tiff, then open each tiff in Photoshop and make your adjustments.

Jane

[jane-e]

I have a 68-page PDF file and I need to adjust each page seperately in PS in order to straighten them out...Is there a method through which I could do that with absolutely no quality loss in the editting process?

Hi

In Acrobat, use the Export PDF toolbar and either export each page to a tiff or click the checkbox to export all images to tiff, then open each tiff in Photoshop and make your adjustments.

Jane

[Tommy J.]

Thank you jane-e, I will do that.

Unfortunately it looks like in that way the size of the new files will be significantly increased, but I guess there's no other way to be sure that there's no image quality loss.

[Tommy J.]

I've already started to edit the pages and save them to TIFF (no layers, ZIP compression) but the new files are quite huge...
Is there any tip to get smaller files without compromising the image quality?

[Tommy J.]

Does anybody know if saving an image as TIFF with JPEG compression (12 level) would result in image quality loss?

[Test Screen Name]

JPEG is a lossy format. There is no exception to this, no "perfect" level. You may not be able to detect a problem, but it will have changed.

[Lumigraphics]

JPEG is lossy, it discards image data.

What you are asking for is impossible. There WILL BE changes to the finished data if you manipulate it. You'll just have to live with it.

[Tommy J.]

I get your point Lumigraphics.

In any case, I aligned the pages, saved each one as lossless TIFF (ZIP compression) and then combined in a single PDF file as intended. The new images look just as good as the original even if you zoom really close. The negative thing is that they turned up too large: The size of the new combined PDF file is about 680mb while the old one was 200mb (68 pages scanned in 600 dpi).