"Toner/Ink Saver" implementation?

[gary carroll]

I have tested (a)on an Apple LaserWriter 16/600, using the specific PPD 
and also using the generic PostScript. (b) Creating PDF and PS to file 
and examining on screen. Output is consistent in all cases.

I will use the CUPS test page as a reference to describe my results, 
which are promising but so far unsuccessful.

The page in it’s default state has a tone bar in the upper center that 
ranges from white at the top and grades smoothly to black at the bottom. 
In the upper right of the page there is a wheel composed of radiating 
hairlines. The lines are solid black, but the give the appearance of a 
gray ball that darkens to the center as the lines converge. A very 
slight moiré pattern is visible.

Setting brightness=200 shifts and compresses the tone range towards 
black. The tone bar is white for about the upper two-thirds, then 
rapidly runs through all the gray levels and hits black at the bottom. 
The important result for the issue at hand is that while grays are 
shifted towards white, black itself is unaffected. The wheel of 
radiating lines is unchanged, pixel for pixel, and black text is not 
affected.

Setting saturation to 50 produces no noticeable change anywhere. (I 
expected this since the documentation says it affects only color.)

Setting gamma=2000 lightens the gray tones in the bar more evenly than 
brightness, but has no effect on black. The wheel of radiating lines is 
unchanged.

Text is unchanged in all of these.

What I am hoping for is to “clip” the black end off the tone range, so 
that the range runs from white to XX% black. I am not sure what the 
percentage will be, and suspect it will vary with the document and type 
of printer… for the sake of discussion, lets say it’s 80%. Thus, white 
would still be white, but all blacks would be 80% gray. I have done this 
under Windows long ago by editing the transfer function in the PPD for a 
particular printer that was used in combination with the Adobe driver, 
but looking at the LaserWriter PPD this does not seem an option, and I 
want it to work on a range of printers anyway.

Michael Sweet wrote:
> gary carroll wrote:
> 
>> I can't seem to detect any change in text documents sent to a 
>> PostScript printer using the brightness=200. Does setting "brightness" 
>> lighter affect text as well as graphics?
> 
>  > ...
> 
> Yes, brightness controls the transfer function used for all colors.
> It should work for all CUPS-based printer drivers - if you are using
> a custom driver of some sort (which prints text directly, for
> example), then that option might be ignored...
>