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I'm converting BMP and TIFF images to PDF. My setting are lossless conversion, but the resulting PDF pages/images are different from the original images in terms of sharpness. Some preprocessing/sharpening is done when I convert BMP to PDF. I want that my PDF has the exact same images that I select, and not some preprocessed variants of those. I configured the conversion to be lossless, but preprocessing even so is done.
How do I completely disable image proprocessing when I convert BMP/TIFF to PDF?
How have you verified that it has changed? Be sure to view the TIFF/BMP at 100% scale and the PDF at a scale that matches the size exactly, as different apps will downsample differently.
You are right, the problem is - I think - that Adobe at 100% has a different scale than IrfanView (I use IrfanView by default for images). Probably Adobe creates the PDF without touching the BMP image, but the problem is that I can't really check that because 100% Adobe scale differs from other image viewer 100% scales, like IrfanView or Windows ptoto viewer for instance.
So do know how to zoom in Adobe page to match that of the page size in IrfanView for instance?
Other viewers use dot for dot pixel mapping (I think), but Adobe does not.
So I need to disable dot for dot in irfanview or whatever or enable it in Adobe. In irfanview, or Windows image viewer I did not found such option.
Is such thing in Adobe?
The problem then is that 100% is different. But Acrobat is not an image viewer, because PDF isn't an image format. A typical PDF might contain actual text, line drawings, and images at different resolutions. There is no dot for pixel mapping possible.
The page size of a PDF is measured not in pixels but in inches/mm. The size of a PDF converted from an image comes from the image size in pixels and the resolution in ppi. So you can control the PDF size in inches by setting a resolution. You can't control the PDF display much; it will be different on each person's screen.
OK, I found the resolution setting in Adobe. I can get a perfect match if I set the Adobe resolution to be exactly the image resolution, so both match 100%.
I think this is the final solution. Although it would be nice an Adobe option that sets automatically the resolution based on the PDF image resolution, so I don't need to set it manually.
Thank you for your support!
Although it would be nice an Adobe option that sets automatically the resolution based on the PDF image resolution, so I don't need to set it manually.
Thank you for your support!
No, that's not the purpose of Acrobat. It indeed does not make sense to convert images into PDF if it is just to have them in PDF.
No, I don't want to just make a PDF from some images. It is a scanned document that I want to OCR scan finally.
Actually I don't understand what you mean by "set the resolution". So far as I know there is no per-documenr resolution setting. Only a personal setting applying to all documents, which doesn't sound useful to you, unless you have a very specialised work.
Open Adobe Acrobat, go to Preferences, from there to Page Display.
There you can set a custom PDF display resolution, or a system resolution, which in my case is 96 pixel/in.
Ok, so long as this works for multiple files for you. And so long as you realise it's YOUR setting - it doesn't go with the file to other people's computers.
I'm wondering how does Acrobat do image interpolation when it comes to resample images to fit with different zoom selections. In my case the interpolation result is not the greatest. Is there a way to select the interpolation method, or Acrobat already uses the best available?
To display on screen, Adobe Acrobat favours speed over accuracy.