Liam Lawless (lawless@vignette.freeserve.co.uk)
Mon, 08 Mar 1999 21:51:51 +0000
Hi all,
After giving it more thought, I've finally come to the conclusion that my
filtration idea won't work - for reasons that were in some of the messages
I've received, but which I failed to "decode".
What I supposed, putting the idea in its simplest form, is that if a strong
magenta light and a weak magenta light are both shone through a cyan filter,
the filter will have a greater effect on the colour of the weaker light.
But the "weak" light in my experiment is weaker only by dint of having lower
candlepower, NOT lower colour saturation - its colour is exactly the same as
the stronger light, and will be altered to exactly the same extent. It is
absurd and preposterous to think differently! If I project a beam of
magenta light through a cyan filter, the colour on the baseboard does not
change as the aperture is altered, so neither will it be modified as a
result of the different densities in the negative.
Well, another failure, but I hope we've all had some fun thinking and
arguing about it. You can bet the guy who invented the wheel didn't get it
right first time... (but at least he got there in the end!)
However, Dave has come up with another idea, a variety of harmonising. I've
thought about this in the past, but not bothered with it much because part
of the appeal of the reversal method, for me, is its speed and simplicity,
and, as I keep saying, I'm happy with results from the "straight" process,
but I'll nevertheless make some comments.
Firstly, no question that it will work, but how well remains to be seen.
I'll certainly give it a go in the next day or two. What we want (and it
might help to refer back to my little block-diagrams in P-F #2) is a cutting
reducer that will "slice" an equal amount of silver off all image densities.
Farmer's is the obvious candidate, but I imagine that it would have to be
made up rather stronger than it would normally be used on prints.
Other means of harmonising negatives could also serve to shorten the range
of an enlarged APH neg: we might, for example, raise the shadows by
bleaching only the lowest densities with a chromium intensifier (and then
redeveloping), or lower the highlights by bleaching out completely in a
halogenising bleach and redeveloping only partially, so that the highlights
are left less than completely redeveloped (and then fixing).
Sil Horwitz has mentioned (offlist) one of his own developers to me, which
sounds just the ticket for controlling highlights on lith. I shan't say
more as it's not my place to do so, but maybe he'd care to come forward with
details at this point... (?)
Liam
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