Color depth conversion in APu

[Gianni Becattini]

Oh no! You again....

The last (I hope) big problem. I wrongly supposed that, setting the APu document color depth to 8-bit, all the images in that document would be converted to 8-bit in the pdf. It is not so. The images "pass" in the pdf in 16-bit, making the pdf so huge that the printer says he cannot process it (8 Gbyte).

Is there a solution different from editing about 800 images by hand? (even with 3.rd party tools)

As always, thanks

 

[Gianni Becattini]

I forgot: every page is an AP document, not jpeg or other.

[NotMyFault]

Would you mind giving the required export settings from your printer, and a screenshot of the settings you used for export?

[lacerto]

Obsolete.

[Gianni Becattini]

Thanks, but probably I am doing something wrong...

I set the document in this way:

and the exporter in this way

but the pdf is produced in 48-bit/pixel (RGB-16)

[lacerto]

Obsolete.

[Gianni Becattini]

Thanks for your very detailed answer. Please tell me that I correctly understood (remember that my aim is to have a reduced size file):

• 8-bit CMYK = 8 bit / color, i.e., 32 bit / pixel - following your instructions I could obtain it, but the file is only 10% smaller (about)
• if I change from RGB-16 to RGB-8 in Photo, images go to 24-bit/pixel and the size reduces dramatically (10 times)

Is there a way to obtain this reduction in an automatic way? I tried many setup but with no success. Probably I am not finding the correct profile?

Thanks again

[lacerto]

Obsolete.

[Gianni Becattini]

Thank you very much.

Eventually, with your suggestions, I could succeed, but with a slightly different setup. I don't remember it exactly, I have it saved in my office computer, tomorrow I update this, but I didn't want to omit thanking you for now...

[Gianni Becattini]

Here I am again. I could succeed with the following settings:

• no change in document setting (RGB/16)
• compatibility 1.4 (Acrobat 5)
• colour space: RGB
• profile sRGB IEC61966-2.1
• convert image colour spaces YES

In this way, the size of the complete file shrunk from 9.1 to 3.4 G. Until now I received no complaints.

Thanks again!

[lacerto]

Obsolete.

[Gianni Becattini]

Thank you very much for your help. Now the problem has been taken out by the Editor, who is finding solutions operating on the pdf file.

In the end of the day, they are getting again big files. In my opinion, the problem is without solution, i.e., if you want a certain amount of information, you need space to store it and also compression has its limits...

Thanks again

[lacerto]

Obsolete.

[Gianni Becattini]

We are starting again the same movie... The printer says that he cannot deal with a 9 GB file and I did my best with tons of tests without finding a solution.

You suggested me to reduce the jpeg quality and this seems have a great impact on the size: producing a CYMK file with the settings below, with 85% the size went down to 2.38 GB. To my unexperienced eyes, it seems perfect, even enlarging much on the screen, but they refuse to follow this way. Considering that the book is only 210x210 mm, could this be a good way?

Thanks

Gianni

[lacerto]

Obsolete.

[NotMyFault]

8 hours ago, Gianni Becattini said:

You suggested me to reduce the jpeg quality and this seems have a great impact on the size: producing a CYMK file with the settings below, with 85% the size went down to 2.38 GB. To my unexperienced eyes, it seems perfect, even enlarging much on the screen, but they refuse to follow this way. Considering that the book is only 210x210 mm, could this be a good way?

I use 85% for jpeg quality since a log time, it is the best compromise between quality and file size. Higher settings gain very little extra quality, but can inflate file size by factor 10. 75% and you get noticeable differences in quality.