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Why is the equivalent to (5% pages) is 3.24 for this image?

Posted: 29 Feb 2008, 12:51
by Awerner
I am evaluating the software and try to understand the calculation of cost per print.

Here is what Epson's standard 5% ink coverage per channel and somehow I don't get it.

I downloaded the image above and converted it to an A4 sized PS image using pixel increasing so that the image stay as sharp as possible.
Then I used the Coverage ratio RGB only (PS, PDF) methode on 300 DPI

Now my question: I was wondering why the equivalent to (5% pages) is 3.24 where my expectation was anything near 1. What do I think wrong?

using the Coverage ratio CMYK+RGB (PS,PDF) comes with the same outcome if using the RGB caculation.

Does this mean: If the printers ink usage is stated to 10000 pages then I can print 1000/3.24 pages A4 of this image?

Thanks for any response

Posted: 29 Feb 2008, 17:57
by support
Here is the 5% per channel page from this site ( ... verage.gif).
Epson writes "show an average of 20.5% ink coverage per CMYK channel (here is what Epson's standard 5% ink coverage per channel looks like".
Sure If you convert it to RGB and measure you get 20% = (4*5% per channel). So it equivalent to 20/5=4 pages with 5% coverage. Considering low quality of this gif you get 3.24. For CMYK you get 5% coverage for each of 4 spots.

Read APFill manual about differences in CMYK and RGB coverage measuring:

And also here is some tips for APFill:

Posted: 29 Feb 2008, 21:02
by Awerner
That was very helpfull, Thank you.

One more question left: In case of most desktop printers the usage will be given by the manufacturer. What in case I want to use the program for e.g. a wide format printer where the maximum number of pages at 5% possible to print is unknown? Or is it always possible to get that sort of information from any printer manufacturer?

Posted: 29 Feb 2008, 23:22
by support
Ususally this info is available from manual or manufacturer website.
For example: ... oSheet.pdf