From: TERRY KING, 101522,2625
TO: Peter Marshall, INTERNET:petermarshall@cix.compulink.co.uk
DATE: 23/05/96 12:13
RE: Copy of: Re: Copy of: Pt negs and coats & brightness range
Hello Everybody
I wrote:
> > I suppose perceptions of 'perfect' are subjective and context sensitive but
as
> > it is possible to get the full brightness range that we are able to perceive
> > onto film and from the film onto platinum/palladium sensitised paper, ie
eight
> > stops, I would like to know what kind of perfection I am missing out on.
> >
> > Is my perception of the meaning of 'brightness range' wrong?
> >
Peter Marshall replied:
>
> It is impossible to get the full brightness range we can perceive onto film -
as
> you can confirm by the simple experiment of photographing a sunlit scene
> containing areas of deep shadow and comparing the print (or negative) with the
> original. Or you might like to use your spot meter to take readings of the
> lightest and darkest points of such a scene.
I am afraid that the facts do not support that view.
Perhaps the mistake arises from a misreading of what I wrote.
I regularly get onto film a greater brightness range than I can see or perceive
in looking at the scene. On a bright sunny day with deep shadow one cannot
perceive highlight detail and shadow detail at the same time but it is possible
to get both onto the film and to print them. We had an earlier discussion about
how many stops it was possible to get onto film and from there onto the paper
when printing in Pt/Pd without dodging and burning in. The practicable range
appears to be about seven and a half stops; beyond that one knows that the
detail is there because it is on the negative, but on the contact print from the
in camera negative the shadow detail is only perceptible in terms of texture or
by holding the print up to the light. With dodging and burning in, and by
maniplation of the development it is possible to get both the highlight and the
shadow detail clearly onto a silver gelatine print. I can show you negatives
and prints in platinum and Richard Ingle's negatives and prints of the same
scene that clearly demonstrate the point. Richard's print seemed unreal to me
because I knew that it did not represent either what one could see or perceive
but the lens and the film and the silver gelatine paper, in Richard's able
hands, could. At the time this led to my concern as to whether there was a
platinum aesthetic. But on reflection I realised that this was my subjective
reaction to reality and that I was being a purist. It would have been quite
possible to get that range into a platinum print by the simple expedient of
dodging and burning in inter-positives and inter-negatives. But it would have
been an artificial extension of perception. I realise that it is possible that
my own perception of brightness range is limited but I have asked colleagues
whether their perceptions were the same as my own. They were. But from the look
on their faces it was clear that they thought that I was bonkers.
I would be grateful for further comment or correction but as far as I am aware
human perception of brightness covers about eight stops. This is somewhat
analogous to the Emerson argument about perception of focus, one may be able to
see into the shadows and perceive the detail there, but when looking at the
highlight detail one cannot see what is in the shadows and vice versa. We have
to shade our eyes to see into the shadows or mask the light box to look at a
transparency.
It is worth adding that film is manufactured to record brightness ranges many
stops beyond our perception for recording events of very great brightness.
>
> This is of course dealt with fully in many of the standard texts - such as the
> Ansel Adams series no doubt on your bookshelf!
Apart from the fact that Adams' concern was with printing onto silver gelatine
with its limitations in the range of tone it will accept from a negative, are we
talking about the same thing ? I am not talking about the density of the print;
I am talking about what detail one can get onto the paper. I can see detail in
seven and a half stops on the film and I can see that range in the Pt/Pd print.
Anything beyond that range goes beyond normal perception of the scene.
> One of the points that I have made before is that when you print a step wedge
> the steps on the print no longer have the same density difference. Eight .3
> steps on a wedge may correspond to a density range of only 1.4 on a platinum
> print.
See previous comment.
This may well give a successful print as the different tones will remain
> different, but the result will be quite different to a print that distributes
> those same eight steps over a density range of 1.8 (or a glossy b/w silver
print
> hitting 2.1). Bigger isn't necessarily better (but different).
How does the difference manifest itself in a straight print ?
Of course bigger is not best; some of my favourite prints have a very narrow
density range.
Terry