I'm disapppointed that, in your usual eagerness to correct me, you
overlook the original puzzle: why my friend's exposures were so slow.
Most of your annotations were thus not much help -- although they did
repeat material we have been over in the past year, for those who are new
and don't want to bother going to the archive. However (also as usual),
while I can see that you're trying to be helpful, you have "corrected"
quite a few things I never said, ie., put words in my mouth, such as:
On Mon, 27 Jan 1997, Terry King wrote:
> For multi colour printing I remain unconvinced that using a step wedge
> tells youanything at all.
I have not recommended the step wedge for a multi color print, tho even
there some of its information may be relevant. But I note again that
especially with issues of this sort (puzzles!) no other indicator can
compare. I'll also add that the kind of quantification thus obtained does
seem lacking from many of your observations. ("Better" is not
information.)
> Just remember that the higher the reflectivity of the pigment, > the
more you will need. So use strong colours to reduce the amount of >
pigment required.>
I'm trying to figure out what you mean by "reflectivity of the pigment"
(refractoriness? density? opacity?). "Reflectivity" is something else. In
any event, your assertion is not entirely true. Pigments that are
identical visually, and even comparable in covering power, can differ in
speed if their *chemistry* differs, as it may well (just as gum arabics
with the same "refractoriness" can have different speeds due to their
chemistry). There is also the difference in sensitivity to UV light at
different points in the spectrum. The 21-step reveals such differences, if
you're interested.
> >As noted, the first manifestation of over-pigmentation is likely to be
> >highlights flaking off.
> Or the shadows.
Terry if you can print so that your shadows flake off before your
highlights you will go down in history.....
As for my question about the relative speed of a 10 % solution of K di
versus a 30% solution of am di, I know you were making a joke when you
said 10 into 30 goes 3 times, but in case some beginners get confused,
I'll note that the print is *not* 3 times as fast, and so I wonder if that
is the correct arithmetic. If anyone else has a suggestion I'd sure like
to hear it. (Mike Ware has pointed out that in any case, for any % above
the smallest concentration, there is a surfeit of dichromate ions: ie.,
the chemistry involved is complex and subtle.)
> Again be consistent . Make up your own gum from a reliable source or use
> Gloy.>
Again, Terry, I thank you for your well-intentioned advice, but, if I may,
will note that I find different gums serve different purposes. For
instance a slow gum is excellent for masking. A low-gloss gum is handy for
subsequent coats where I don't want a lot of shine. Etc.
However, Terry, I am extremely gratified that you ratify and even
*approve* my habit of developing at room temperature, saving warm
water for an extra push ("a very effective approach" you call it),
especially since you have in the past insisted on warm water, & quite
recently, as I recall. (Maybe you're just buttering me up...? )
Whatever, I close on a cheery note (subject to your corrections of
course),
Judy