Good to hear from you. You don't make your presence very often. :)
<< Phalo blue is a colour which can stain easily if you overload the gum mix
it has a high tincture strength, I use it at 1+ 8 in my tempera print work
and do not have any problems as long as I do not go below that
dilution.
I found it might be that my "Winsor blue" is not really "Pthalo blue." I
switched to Holbein Pthalo blue and it didn't stain at all.
>> Another tip is to print the blue last,then print a clear gum coat
with no pigment present ,this acts as a cleaning coat and will remove any
slight stain, however the paper must be correctly sized in the first place
for this cleaning to work efficiently, if the strain has penetrated the
paper fibre you stand no chance of removal.
I don't understand the logic behind this, but I will give it a try. You mean
that, by printing another clear coat of gum it will clean up the stain? Do you
mean actually coating a gum+dichromate mix without pigment, then expose and
develop?
>> A slight black stain is hard to detect as the eye adapts through
simultaneous contrast effect and just does not see it unless the stain is
gross
Yes, maybe I shouldn't have said "cleared completely." I did compare the
density of a unexposed, undeveloped paper with the "clear" part of a processed
paper, and it did show some stain; but I haven't further to test to see if it
was dichromate stain or the pigment stain. But with black pigment only, this
staining, whatever reason it is, is not any any visual problem especially if
your composition is that the emphasis contrast of lighting (dark against
light).
>> It may be a pain Dave but don't cut the testing remember "If you wont to be
the best you have to test"
>>
Good advice, I will do more tests although I am actually a test freak that I
have to balance and sometimes force myself not to test. :)