12-13-2017 04:51 AM
Hello, I have this printer and accordning specifications this printer can scan up to 1200 dpi:
Scan via TWAIN/WIA, Scan to PC, Scan to WSD, Scan to Email, Up to 1200 x
1200 dpi (4800 x 4800 dpi enhanced) resolution, Colour, Black and white, 8-bit
However, I can't select more than 300 dpi (in WSD driver or in scan to pc settings).
My question is how I can scan in higher resolution with this machine?
12-13-2017 01:06 PM
The following statement is very simplified for easier consumption, the links that proceed after it are not, and are certainly more correct.
300DPI and 1200*1200DPI are the same number when using a CMYK device.
The following is a print example using higher end printers, but it works both ways.
You actually are always printing at 2400*2400 DPI, because that is what the printer does by hardware.
What you see in the driver is how the jobs are interpreted and ripped.
So the Printer takes your job and renders it according to the resolution dropdown (600 or 1200) Obviously file size changes massively dependent on which you choose. 1200 is great for text (crisp), 600 is great for images (colors, gradients, saturation). Color issues can and do occur at 1200 (faded, de-saturated), not always, but often enough.
And here is where the real difference is noted. 1200DPI does not equal 1200*1200DPI, they are entirely different measurements.
1200DPI is the amount of dots used to make a digital image appear on screen total within one inch.
1200*1200 (In the C75 it is 2400*2400) is very different, in the CMYK world, unlike the RGB, you divide resolution by the toners.
So with this CMYK device you have the 4 colors, so you divide 2400*2400 by 4.
So each color (CMYK) prints 600*600 DPI, when all 4 colors are laid down, there are 2400*2400 DPI.
In the case of scanning, it scans to get the CMYK in 1200*1200, then converts to RGB which will result in 300DPI.
Some more heavy reading on the issues
12-14-2017 02:43 AM
Hi, thanks for reply. However, I'm not much clever from this. I was asking particulary about scanning because in prospects it's written that it supports up to 1200x1200 dpi so I would expect it's optical resolution of the scanner. But scaning to PC or email allows only up to 300 dpi. I wonder why because my old 5 years printer allowed up to 600 dpi when scanning to pc but I expect it's because of some limitations with this Xerox printer.
However, I've found out that when scanning with TWAIN driver it allows to select up to 4800dpi (I believe this is enhanced resolution). So if I understood you correctly, this means optical resolution is 1200dpi right ? I was trying to scan at this resolution 1200dpi and besides the image was really sharper it was also much darker in comparison as if scanning at 300 or 600dpi. Do you have idea why is that and how to prevent this?
01-19-2018 10:26 PM
Okay... that was a wonderful explaination about 4-bit printer, but what about 24-bit scanning? What is the actual resoltion of the scanner and how can we scan at the settings that are claimed as possible in the service manuals? I have a 3015NI that the documentation says wills can at "upto 1200x1200 dpi" but a xerox WIA driver that will only allow 600dpi. I don't see any downloads for TWAIN drivers for windows 10 to get up to 1200 or 4800 or whatever, and haven't found any way to enable "driver conversion" in the WIA driver yet either.
Any additional insight is greatly appreciated.