From: TERRY KING, 101522,2625
TO: Peter Marshall, INTERNET:petermarshall@cix.compulink.co.uk
DATE: 24/05/96 14:40
RE: Copy of: Re: Copy of: Re: Copy of: Pt negs and coats & brightness range
Peter
>
> Terry I still know you are wrong and if you actually go and do it you will
> see that you are wrong (or that you are in urgent need of a visit to the
> opticians.) Unless you restrict yourself to very limited subject matter
> there is always detail in either or both shadows or highlights that you can
> see but will not be recorded on film.
That is demonstrably false. Remember 'at the same time'.
The eye may not instantaneously have a
> particularly long scale (I'm not sure on this), but certainly it can look
> into shadows and adjust to build up the 'picture'. So we can and do see
> the highlights and the shadows you talk about with ease.
What I said was that we cannot perceive detail in the shadows and in the
highlights at the same time. I have a strange feeling that that is a truism.
> > This inability of the photographic process is indeed one of the basics that
> one has to teach in learning to photograph in black and white.
The inability is that of the paper to accept a wide range of tones from the
negative. That is what the zone system is all about. To a great extent self
masking obviates that difficulty. You are talking about photography using silver
gelatine paper.
It is also
> enshrined in the zone system where you have to learn to judge 'significant
> shadow detail'.
>
When one is working with processes where the paper will accept all the stages on
the step wedge, such as carbon or platinum, the zone system is largely
irrelevant.
> Adams in one of his books was talking about negatives. I imagine you still
> use them. Of course you will get exactly the same sort of message (but with
> more math(s)) from any book on sensitrometry.
Adams is talking about negatives that have to be adjusted to take account of the
limitations of silver gelatine paper. I have negatives that show detail from
0.15 to 2.8 and contact carbon and platinum prints made from them showing detail
across that range, whereas the ideal negative for a silver gelatine print has a
range of about 0.9, hence the zone system.
>
> In a monochrome print we may discern a hundred different shades of grey -
> but these could be between densities of 0.3 and 1.3 or between 0.05 and 1.9
> and the results would visually be quite different.
Yes. Who is disagreeing ? But here you are talking about reflected density.
> Would you like me to lend you a copy of Eggleston's 'Sensitrometry for
> Photographers'? It claims to be a comprehensible and practical book for
> photographers!>
What I would like is an extract from your authority that contradicts anything I
have said, remembering the context.
Terry
I raised this as I thought that there might be a point of significance in
relation to our perceptions of prints made using alternative processes. I am not
sure, however, that a discussion on sensitometry is appropriate to the list..