[scribus] CMYK Values Overwritten

[Gregory Pittman]

On 06/16/2011 06:52 PM, Owen wrote:
> On Wed, 15 Jun 2011 21:45:15 -0600
> Mike Sleger<chappa-ai at q.com>  wrote:
>
>> If I define a CMYK color as 0.00%, 30.00%, 60.00%, 5.00% and save the
>> change, then go back and review the color, its stored values are
>> instead 0.00%, 30.20%, 60.00%, 5.10%.  (If I had wanted 30.20 and
>> 5.10 I would have specified them.)  Similarly, another color defined
>> as 100.00%, 41.00%, 0.00%, 55.00% is actually remembered or stored as
>> 100.00%, 41.18%, 0.00%, 54.90%.  Is this normal behavior that people
>> just accept because it's "within tolerance limits"?  Can't the
>> program keep track of single-precision floating-point values?  If
>> color values are changed, what else gets changed?
>
>
>
> I would suggest that this is a minor bug that should be reported at
> http://bugs.scribus.net (I cannot find such a report)
>

As I look at this a bit and check some things, it may be that there is a 
problem with the precision of these percentages, decimal values, and the 
hex values.

Colors in RGB can be 0 to 255, in hex 00 to ff. When I set a value for a 
CMYK color in Scribus, then save the file, the color will be saved in 
hex, which may not have the precision at a level of precisely 30%.

This is not to say that this is not a bug, but if we consider that your 
30% will be converted to hex, then converted back when you check it in 
the colors dialog again, maybe it isn't surprising it might come out as 
30.2%.

In fact, you can observe the phenomenon in the dialog by making values 
for CMYK, switching to RGB, then switching back to CMYK.
My guess is that a value in CMYK of 30% vs 30.2% has little meaning.

Greg