The article that was accompanied by pictures showing normal, over &
under contrast and also normal, under and over exposure. The change in
the contrast was by adding 20% of water to increase contrast and 5g/Litre
of Pot. Bromide to soften. I
preferred the normal but there was not a lot of difference. A small
change in filtration was made to the higher or lower contrast but there
was no mention of any filtration for the normal contrast The three
different exposures were 2,4 & 8 secs with no filtration &
normal contrast activator. I preferred the 8 secs. although the 4 secs
as the correct exposure by programmed - exposure automation.
Unfortunately no prices were given but even if it compares with
Polaroid, it does at least allow any number of prints required and
appears very good-tempered.
The author made identical exposed prints of the same slide, giving 90,
120, and 180secs. in the activator. All 3 pictures were practically
identical. There appears to be no good reason to ex end activation time.
This seems to indicate the materials tolerance for processing errors.
Exposure latitude is also enormous . In an initial experiment, a sheet
was exposed strip-wise to have exposures of 1, 2, 3, 5, & 8 sees.
Even so, it was very difficult to see the line between neighbouring
density strips.
The
exposure side of the paper is jet black ...after exposure, it changes to
a saturated hue of green and the picture side is white. Because the
sheets are not corner notched in the normal way to identify the emulsion
side, the difference must be felt with the finger, the black side being
smoother than the white. If the mistake of loading backwards is made it
does not matter. Just turn the paper over when the exposure ‘on the
wrong side has been made. The material is absolutely opaque and no light
will get through the wrong way. Incidently, because of back to front
exposure the slides have to go in the enlarger carrier emulsion side up.
Exposure ‘and filtering proved easier than the author had ever
experienced. With no filter there was a slight reddish bias, corrected
by 15 “Agfa” units of cyan. Thereafter, this was the basic filter
pack for most of the prints made over a period of five clays.
In the few cases where correction was needed, this tended to be in big
jumps of more than 20 units, rather than the very small changes usually
found with other materials. When there is a need for correction it seems
to occur far more frequently when using altered activator solutions to v
ry contrast, than with the normal dilution. The normal solution is
slightly soft and Agfa recommend adding 10% water to increase the
contrast. The author found 20% more useful. This requires the addition
of yellow and cyan filers to counter a magenta shift. (also an increase
in exposure). It is interesting to note that two trays of activator were
left just covered with a sheet of cardboard over the weekend and were
perfectly useable. To reduce contrast Agfa recommend 2g per litre of
Pot. Bromide be added to the normal solution. The author: found 5-8g
more useful. This gave a bluish cast. The article corrects this with
yellow & cyan filters, the same as the magenta cast above. Surely it
should be yellow & magenta in this case. Extra exposure was again
required.
The article then goes on to discuss in camera use. Agfa claim a speed of
16 ASA, but the author found 25 was the best to assume, using the normal
activator. With the 20% dilution a speed of 40-50 ASA is achieved. The
author’s reservations, if any, about the material, as used for prints
from transparencies were: The glossy surface is not completely smooth.
The sharpness could be improved. He considered it adequate but not as
good as conventional colour papers...but hairline sharpness is not a
speciality of diffusion transfer material.
He sums up by saying he is sure many changes will have been made by the
time it reaches this country and that the material will have been
improved. No mention is made or what it will cost. However it all sounds
very interesting.
Well there you have it... This report gives the new Agfachrome-Speed
quite a fair comment and for anyone just planning to venture into
reversal printing it does seem to have a lot going for it, We look
forward to a report from any C. R.C. member who tries this process in
the coming months.