> No Wayde, what I had run into was utter LACK of scientific method. As far
> as I can tell, Anderson simply *reasoned* that the way the pigment and the
> gum alone did or did not release from the paper would tell you something
> useful about the way the pigment would work in an emulsion, that is with
> DICHROMATE and EXPOSURE added, but never checked to see if his assumption
> was correct.
This is pretty much the same kind of reasoning that you have when choosing
the "let's only change one variable kind of experiment". That approach
makes the assumption that the variable changed is not affected by those
that you chose to hold constant (or leave out in this case). As you have
noted, that assumption should be tested.
> Leaving aside any other kinds of "variables" -- ratio of pigment, of gum,
> of dichromate, etc.-- he was out of it at the outset. Every single one of
> the gum pigment ratio tests was irrelevant, meaningless, beside the
> point, and useless, however many variables he did or did not change at
> one time or in a schemed manner.
Actually I wasn't trying to ague that. In fact I think we're probably in
fairly violent agreement. What I was trying to add is the observation
that such failures in experimental design and interpretation are not
uncommon.
> Another issue that I didn't get into in my overly long post about the
> "Ansel Adams" gum chapter was the assumption that there CAN be an "ideal"
> emulsion. It totally depends on everything else, such as which layer
> you're doing, one of many, or a single, what you want it to do, how you're
> going to develop it and what's under it -- not to mention one of the most
> important variables of all, namely what paper you're putting it on.
> Different sizes and textures of paper take emulsion differently.
No argument here.
Oh, by the way. After reading your article on gum printing in your
"Journal of Post Factory Photography" I was able to make a decent gum
print. I liked it anyway. Thanks - I think <grin>.
- Wayde
(wallen@boulder.nist.gov)