Digital BW, The Print

There is an interesting thread in Roger Gailbraith's color management  
forum that addresses the question of gamma 1.8 vs 2.2 on the Mac.  See  
in particular Ian Lyon's comments at this point in the thread:
http://www.robgalbraith.com/ubbthreads/ 
showflat.php?Cat=&Board=UBB3&Number=146760&Forum=All_Forums&Words=gamma% 
201.8&Match=Entire%20Phrase&Searchpage=0&Limit=25&Old=1week&Main=140325& 
Search=true#Post146760
The url is long, so you may have to copy/paste to use it.

There are several workflows and RIPs available for printing B&W.  The  
QuadTone RIP and OPM/IJC use grayscale input, but the MIS VM/Ultratone  
workflow uses curves applied in RGB mode prior to printing.  I don't  
know of any specific books that describe/compare these workflows in  
detail, but perhaps other group members may be able to help you.

On Monday, June 30, 2003, at 04:12  PM, kiwikale wrote:

> Ok I can see the differences in the step file and I will take another  
> look at/redo the
> test prints.  Can I ask why Gray Gamma 2.2 vs 1.8 (ie the default  
> gamma for Macs)?
>
> Also there is an enormous amount I have to learn about curves etc.   
> Where is a good
> place to start?  I was reading some of the workflow material on the  
> MIS website.  I
> guess I can simply "follow instructions" but that isn't really enough  
> for me.  I would
> like to understand this stuff - at least partially.  For example, I  
> was really puzzled as
> to why one would "Edit the image in grayscale mode, save it, and then  
> convert the
> mode to RGB for printing."  The color world seems relatively straight  
> forward with the
> use of ICC profiles while B&W seems to be all over the place.  Any  
> pointers to
> tutorials/books etc would be greatly appreciated.  I need to start  
> with the basics.
>
> (Also if anyone knows any good courses in this stuff in the London  
> area I would
> greatly appreciate it.)
>
>
>
>
>
> --- In DigitalBlackandWhiteThePrint@yahoogroups.com, Carl Schofield  
> <scho@m...>
> wrote:
>> You should see a dramatic difference in the prints made with a gray
>> working space of gamma 2.2 and Dot Gain 15, if the image file has been
>> converted to those respective working spaces before printing.  Try the
>> following to make sure your settings are correct and that you have an
>> image file that is properly tagged:
>> 1. Set your gray working space in Photoshop to Gamma 2.2.
>> 2. Open the 21-step.psd file (from the QTR images folder) in  
>> Photoshop.
>>   It should be already tagged as gray gamma 2.2, if not convert it.
>> 3. Page setup - select your QTR 2200 printer from the list in "Format
>> for:"
>> 4. Print with preview - you should see Source space selected and
>> Document: gray gamma 2.2 and Print space: Profile should be set for
>> Same as Source.
>> 5. Print: make sure again that your QTR 2200 printer is selected in  
>> the
>> printer list
>> 6. printer features, basic: matte paper, 1440x720 Highest quality,
>> photograph, adaptive hybrid, and seven color.
>> 7. printer features: QTR settings, output mode: quadtone rip, curve 1:
>> 2200-warm, curve 2: 2200-cool, blend: 50-50 (or just select one curve
>> with blend at 100-0).
>> 8. print
>>
>> Here is a plot showing the density curves for the above mentioned  
>> file,
>> printed as described above and printed again after conversion to a Dot
>> Gain 15 working space:  http://homepage.mac.com/scho/comp.jpg
>> I think you can clearly see that the densities are higher for the Dot
>> Gain 15 print and that this print is also flat in the shadow area.
>>
>> On Sunday, June 29, 2003, at 03:29  PM, kiwikale wrote:
>>
>>> --- In DigitalBlackandWhiteThePrint@yahoogroups.com, Carl Schofield <
>>> scho@m...> wrote:
>>>>
>>>> On Sunday, June 29, 2003, at 06:36  AM, kiwikale wrote:
>>>>> So far I have just run 3 test prints using the settings
>>>>> suggested/corrected in
>>>>> earlier postings (now print space in PS "same as source", 1440x720
>>>>> Highest
>>>>> Quality etc): Roy's QTR (2200) neutral and warm and then a straight
>>>>> Gimp
>>>>> 4.2.5.
>>>>>
>>>>> In the 2 QTR prints I found I lost a lot of detail in the shadows  
>>>>> vs
>>>>> using the
>>>>> Epson driver (defining the print space in PS as the ICC profile for
>>>>> watercolor
>>>>> paper with the matt black and no further "color" mgt).  The prints
>>>>> were as if
>>>>> there was a loss of about 1/2 - 3/4 stop exposure.  However, the
>>>>> Epson
>>>>> driver
>>>>> tends to be plagued by a degree of metamerism as we all know.   
>>>>> Tough
>>>>> trade
>>>>> off as in the test print I did the metamerism was not that bad and
>>>>> the
>>>>> loss of
>>>>> shadow detail in QTR was.  I guess this is because with QTR the use
>>>>> of
>>>>> color
>>>>> is restricted to govern metamerism and hence tonal range is  
>>>>> reduced?
>>>>
>>>> I was able to reproduce your problem with poor shadow detail and it
>>>> appears to be due to the Dot Gain15 gray working space you were  
>>>> using
>>>> in Photoshop.  I suggest that you use gray gamma 2.2 instead to
>>>> eliminate this problem and if your file has the Dot Gain 15 profile
>>>> imbedded make sure it is converted to gamma 2.2 in Photoshop before
>>>> printing.  You should then be able to get good shadow detail with  
>>>> the
>>>> 2200 profiles.
>>>
>>> Hmmm..... I tried this but to little avail.  I also tried Gray Gamma
>>> 1.8 which I
>>> note PS says is the default gamma for Mac OS computers like mine.   
>>> All
>>> three
>>> prints are, as best as I can tell, identical.
>>>
>>> I am wondering if the effect that I am witnessing is simply the Epson
>>> driver
>>> "pushing" the exposure a tad.
>>>
>>> At any rate, I am getting even more puzzled by a "same as source"
>>> workflow.  I
>>> went through the videos on the piezography website today.  Their path
>>> of
>>> establishing an ICC profile for a particular ink, paper, printer
>>> combination
>>> makes intuitive sense to me.  You can proof setup and, theoretically
>>> at least,
>>> what you see is what you get.  That is, the mapping of colour or
>>> grayscale
>>> reproduction (as I understand it)  is done within PS at the proof or
>>> print with
>>> preview stage and not by the print driver.  In a same as source
>>> workflow any
>>> mapping is (as I understand it) done outside of PS and so changing  
>>> the
>>> workspace in PS should not affect the output (assuming the print
>>> driver is
>>> equally adept at mapping all of the various PS workspaces).   
>>> Therefore
>>> I am
>>> somewhat comforted to find that it did not affect things today else  
>>> my
>>> general
>>> understanding of all this stuff would have been really screwed up.
>>>
>>> When Gimp or others say they have tuned matt black and watercolor
>>> paper for
>>> the Epson 2100/2200, are they in part saying that (a) the driver can
>>> recognise
>>> automatically whether matt is loaded and (b) therefore when you  
>>> select
>>> watercolor paper it loads and uses a profile for that printer, matt
>>> ink,
>>> watercolor paper combo?
>>>
>>> Confused....
>
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