"Now you can make
professional quality colour enlargements from any colour negative
film (e.g Kodacolor, Agfacolor etc) as easily as black &
white!" The 'Paterson Color Print Kit' contained chemicals
and 10 sheets of ½ plate enlarging paper, plus the 3-colour
additive filters, a filter holder and a safelight screen, for
£4.17s.6d (£4:88p). Also available separately, developer
and bleach fix were priced at 8/6d and 11/9d respectively (43p
& 59p). The Pavelle paper was available in 10 sheet packets
of half plate, whole plate and 10"x8" at 13/9d, 23/7d
& 33/2d respectively (69p, £1.18p & £1.66p).
The first test below is taken
from 'Colour Photography' magazine for March 1963.
The BJPA for 1963 also contained a brief report.
'Colour Photography' magazine
published diy formulae for developer, stop-bath and bleach fix
in their September 1963 issue.
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'Colour Photography' magazine
for March 1963 includes a 2-page review of the Paterson Colour
Print Kit. |
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Above is shown (unfortunately
in b&w !) the result obtained by the reviewer on a sheet
of colour paper using the Paterson-Theilgaard exposure calculator. |
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If the first test is grossly
over or under exposed it is better to correct for density before
attempting any colour balance correction. A heavily over-exposed
print with a cast can show a correct balance when the density
is put right. When you are fully satisfied with the appearance
of the test print go ahead and make your final print . . .
When masked negatives (such
as Ilfocolor or Kodacolor) are being printed, the cyan basic
filter must be placed over the negative during all operations.
This serves to even out the exposure ratios which would otherwise
be affected by the orange coloured mask.
I made tests with Kodacolor,
Gevacolor and Agfacolor negatives and in each case the final
print was satisfactory.
Several points arose during
the tests which may be of interest. The filter holder, for example,
is designed to clamp on to the lens barrel so as to make it suitable
for any enlarger. If only one enlarger is to be used it would
be far better to attach the filter holder to the enlarger's red
focusing-filter stem by a small bracket, so that the lens aperture
can be altered without removing the filter holder. The basic
cyan filter is made to fit over the negative carrier. Any dust
or marks on this filter will therefore register on the paper
when the lens is stopped down. The basic filter should be mounted
over an aperture in a piece of black cardboard cut to fit on
the enlarger's condenser or diffusing screen.
Now a black mark for the manufacturers!
Every sheet of paper in the kit supplied to me had a deep score
across it - in the same position in each case. They will need
to do better than this if they hope to sell colour paper on a
highly competitive market! And is it entirely necessary to supply
only ten sheets of paper per kit when the solutions will process
twenty ?
Nor can I agree with suggestions
regarding processing latitude. Under-exposure and overdevelopment
- which is what processing at 85F amounts to - can cause many
failures with colour materials due to the inherent softness of
the emulsion, colour casts caused by crossed characteristics
etc. I know that this is done commercially but I would suggest
that it is better for the amateur to stick to his well-tried
68F processing and obtain the slight variation in contrast possible
by developing from four to six minutes, with four as a standard.
The basic exposure for the
calculator I found in all cases to be sixty seconds and not thirty
seconds as stated in the booklet. This would halve all the factors
given in the table for example, for two minutes basic exposure,
the times would be multiplied by two instead of four. Otherwise
- full marks.
At £4.17s.6d (£4.88p)
for a complete colour printing system it is remarkable value
for money. Cost per print depends on the number of tests necessary.
Assuming, for a start, that two sheets of half plate paper are
used to produce one half plate print, the cost is about 4s.9d
(24p) per print; but as more experience is gained this will be
reduced to 3s.6d (18p) or less. If a whole roll of negatives
has been exposed at one time under the same conditions, it should
be possible to print the whole roll with a test on only one negative
- in which case the cost will be about 2s.8d (13p) per print.
This compares extremely well with a commercially-produced half
plate at an average price of 9s.0d (45p) - which in all probability
may not be as satisfactory as the one you produce yourself!
Is the process efficient ?
Well, I started mixing the chemicals at 1 p.m. on Saturday, then
set up the enlarger and had a satisfactory print by 4 p.m. -
and I had never even heard of the kit before the previous evening,
when the editor sent it to me for reviewing. And in all cases,
and at every step, I tried to forget any previous knowledge of
colour processing and follow only the instructions provided.
Have a go! You will not regret it, and you will have taken the
first step in a fascinating new field of colour work.
K. A. LOMAX
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The PATERSON COLOUR PRINT
KIT
"Experiment with new 'quick-way' printing"
WELL, IT HAD TO HAPPEN sooner or later, and at last the patience
of the amateur colour enthusiast is rewarded. The Paterson Colour
Print Kit enables anyone to make his own colour prints with any
type of enlarger, and with a total processing time of only
seven minutes ...
More than just a new print
process, the Paterson Colour Print Kit is a complete colour printing
system - the Pavelle system - centred round the ingenious Pavelle-Theilgaard
Exposure Calculator.
This simple little gadget enables
one to obtain the first test print with the minimum of paper
and delay. But let me make one point quite clear; there is no
device available - at any price - which will assess any negative
for exposure and give the necessary filtration factors right
off the cuff . . . except by sheer coincidence ! When the best
results are aimed at, there is no substitute for a test print.
What these devices will do, however, (including the Pavelle-Theilgaard
Exposure Calculator) is to provide the basic exposure for this
test print with the least trouble.
It consists simply of three
coloured step-wedges - red, green and blue - in a book-form carrier
accepting a piece of paper 3x2in., and a fourth column containing
a series of numbers from 1 to 48. Its method of use I will explain
a little later.
The Paterson Colour Print Kit
consists of the exposure calculator with its associated diffusing
screen, a filter holder designed to attach (by four rubber-tipped
set screws) to the enlarger lens, a set of red, green and blue
printing filters mounted in a card slide, a basic cyan filter
for use when printing masked negatives - such as Kodacolor -
a safe-light screen, a packet of ten half-plate sheets of Pavelle
colour paper and the necessary developer, stop bath and bleach-fix
chemicals in powder form. There is also a comprehensive instruction
manual which gives a certain amount of colour printing theory
as well as instructions on how to use the kit.
Although each operator will,
in time, develop his own printing technique, perhaps it will
help the less experienced if I describe the way I used the Paterson
kit for the first time, taking a Gevacolor negative as an example;
and assuming, of course, that the chemicals have been made up
according to the instructions.
Starting point
Focus the negative at full aperture to half-plate size on the
baseboard, then stop down to flu. Now attach the filter holder
to the lens - taking care not to alter the aperture - and lay
in it the plastic diffusing screen. Although a safe-light screen
is provided in the kit I have never used one when colour printing,
and prefer to carry out the following steps in total darkness.
Take a piece of half plate
paper from the packet and cut it into quarters by folding it
in half, then in half the other way, tearing across the creases.
Insert one piece in the Pavelle-Theilgaard Exposure Calculator
and place in the centre of the image area of the masking frame,
filter side up.
You will find a paper-clip
handy to hold the calculator closed when the paper is in it.
The other three small pieces should, of course, be returned to
the packet which, incidentally, I always keep in a whole plate
box. Switch on the enlarger and expose for exactly sixty seconds.
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I use a shielded torch for
timing this - about a quarter inch aperture covered with two
layers of red or green paper - and a stop watch. These are under
the enlarger table with the enlarger switch down on the floor.
Still in total darkness, develop
the exposed paper for four minutes at 68F; stop-bath for one
minute, and bleach-fix for two minutes.
The room light can now be switched
on and the test piece washed until the base is white - two or
three minutes under the tap. This 'print' will have on it a list
of numbers and a yellow, magenta and cyan wedge each marked with
the initial letter of the filter used to produce the image -
B, G and R for the blue, green and red filters (see illustration
- above). Look for the
lightest step of each colour which is fully covered; and note
down the corresponding numbers from the numbered column. These
are the exposures in seconds for each of the three printing filters.
With some types of negative
it is necessary to apply a correction factor to one of the exposures
- these are listed in the instruction book, but in the case of
Gevacolor I found that correction was unnecessary.
Now remove the diffusing screen
from the filter holder and insert in its place the filter slide
with the red filter in position under the lens. I always expose
in the sequence red, green, blue - not the reverse recommended
in the instructions. In practice I suppose it makes no difference
at all.
Back into darkness . . . place
a second quarter sheet of paper on the baseboard where an easily
recognized colour will record. This must not be a heavy or bright
colour (such as a post box) but a hue which is known to be a
near neutral; or a flesh tone. This is to enable subsequent corrections
to be made more easily.
Expose through the red filter
for the appropriate time. Now carefully slide the filter holder
across until the green filter is in position. This must be done
by touch alone, but as the slide is notched it is quite easy.
Expose for the green filter time and repeat for the blue filter
time. A point worth noting is that the lens aperture should be
set so that no exposure is less than ten seconds. A half-second
error in ten is only 5 per cent - but a similar error in two
seconds would be 25 per cent, which would greatly affect the
colour balance.
Process the paper exactly as
you did the initial test . . . then examine the result.
Only experience . . .
From here on it is a case of experience, which can only be gained
by practice. The print may look correct or it may show an error
in density, colour balance or both. The skill in colour printing
is to know just how much of what kind of correction to apply.
The instruction manual deals with this point sufficiently to
provide a basis for experiment.
Having assessed any necessary
correction it is advisable to expose and process a further small
piece of paper before making the final print. This will serve
as a check on your judgement and calculations and should avoid
wasting a full sheet of paper if at fault.
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PAVELLE-THEILGAARD CALCULATOR
This is an ingenious device
consisting of three step wedges-one red, one green, one blue-
mounted on a hinged flap. The base holds a piece of colour printing
paper 4½ x 6 cms.
Certain preliminary tests have
to be carried out to take individual working conditions into
account, and these experiments take a fair amount of time to
execute, perhaps an evening. As a result of filling in cards
supplied with the data found it is possible to go ahead with
finished prints after a quick test, using either the additive
or subtractive systems.
Having established the basic
charts the procedure is as follows: the negative is put in the
enlarger and focused up to the required size. After stopping
down the lens, a diffuser is placed over it, and the enlarger
switched off. The room light is turned out, and a piece of colour
printing paper put in the calculator, and the flap closed down.
Next a timed exposure is given, after which the paper is developed
in the usual way, put in a stop bath and then fixed in a neutral
fixer. The light is then turned on and the test examined. The
lightest step visible in each wedge is found, and the number
opposite to it is read off. By referring to the chart it is simple
to calculate the three relative exposures by the additive system,
or the correct filtration with the subtractive method. With most
negatives an acceptable colour print will result by proceeding
on the information given.
The great advantages are the
saving of time and material spent in testing.
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The description alongside of the Paterson-Theilgaard
Calculator, is taken from the booklet "All about Printing
Colour Negatives", by Felix Smith.
The scale on the calculator
reads 1, 1.3, 1.6, 2, 2.5, 3, 4, 5, 6, 7.5, 10, 12, 15, 19, 24,
30, 38, 48.
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'Colour Photography'
magazine for September 1963 includes an article on 'Cutting the
Cost of Paterson Colour Prints', again by K.A.Lomax. |
The Paterson Colour Print
Kit, as it stands,
is probably the cheapest way for the amateur to produce his own
colour prints, but it is obviously even more worth while if he
can reduce the initial cost, and that of replacements, when these
become necessary.
Each part of the kit is available
as a separate item, so it is possible to build up a print process
kit by purchasing only those items which cannot be made easily
or cheaply and by using substitutes for the others. Taking the
items of the kit individually we can easily see where a suitable
adaptation can save cash.
For the printing filter holder,
for example, all that is really required is a light metal or
cardboard attachment which will fix to the enlarger's red swing-filter
stem, and carry the printing filter slide.
The printing filters can be
mounted in a simple slide cut out of cardboard -¦ I used
an old print mount - and painted matt black. Two pieces of card
each measuring 6.5x2.25in. are required. In each piece cut three
holes 1.5in. square, equally spaced along the card. The three
filters are held sandwiched between the cards, and notches are
cut in the edge of the assembly so that each filter in turn can
be correctly centred under the lens in the dark.
Starting point
The filters I recommend are the Wratten 29 (red), 61 (green)
and 47B (blue), costing 2s.6d each, as 2 in. gelatin squares.
Apart from the red, the filters
supplied with the Paterson Kit are not sufficiently narrow cut
to produce the best print possible from any given negative; the
blue filter in particular transmits a large proportion of unwanted
green, therefore tending to overlay the yellow with magenta.
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When the Wratten narrow-cut
filters are used, the exposure times determined by the Theilgaard
exposure calculator must be modified, and I have found a good
starting point is obtained by doubling both the green and blue
times given by the calculator.
The basic filter - used when
printing masked negatives such as Ilfocolor and Kodacolor - is
effectively replaced by an Ilford 803 cyan.
Although substitutes can be
made for the Theilgaard exposure calculator and its associated
diffusing screen, the use of an electronic densitometer would
be required for easy calibration. These two items are much better
bought, and together cost 22s.1d. (£1.10p)
The Pavelle paper must, of
course, be bought and the most economical size is undoubtedly
10x8in at 33s.2d. (£1.66p) per packet of ten sheets. One
sheet will cut into twelve pieces for the exposure calculator,
or four handy-sized en-prints.
Excellent results
Apart from the paper, the items requiring most frequent renewal
are the processing chemicals, and I have had excellent results
from the following formulas:
Developer
Stock Solution A
Droxychrome 25g
Potassium Metabisulphite 6.5g
Water to 125cc
Stock Solution B
Sodium Sulphite 5g
Sodium Carbonate 200g
Hydroxylamine HCl 5g
Potassium Bromide 1.5g
Water to 1litre
Use, 1 part A, 16 parts B & 23 parts water.
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To make up a working
solution direct, the formula is:
Droxychrome 5g
Sodium Sulphite 2g
Sodium Carbonate 80g
Hydroxylamine HCl 2g
Potassium Bromide 0.6g
Water to 1 litre
Although the Paterson developer
appears to contain rather more Potassium Bromide than the substitute,
I prefer the prints produced by this formula.
Stop Bath
5 % solution of Potassium Metabisulphite. Bleach/Fix
Water 350cc
Amfix 150cc
Iron Sequestrene 65g
Sodium Carbonate 8g
Potassium Bromide 25g
Water to 600cc
Two points worth noting. If
Pavelle prints are to be glazed, we find that a ten-minute soak
in 10 per cent Formalin solution - followed by a brief rinse
- is a great advantage in hardening the emulsion; and also helps
to stabilize the dyes. And finally, the Theilgaard exposure calculator
will, of course, work with any other process; so that if - for
example - you are already printing Ektacolor or Agfacolor by
additive filters, this calculator alone can save hours of time
in assessing negatives.
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The 1963 BJPA
also describes the Paterson-Pavelle Process, distributed by R.F.Hunter Ltd, 51-53 Gray's
Inn Road, London, W.C.1. "The procedure is simple. First
the filter holder is attached to the lens mount on the enlarger
and a diffusing screen is placed into the holder. This integrates
all light coming through the colour negative. Next the Pavelle-Theilgaard
exposure calculator is placed on the base board with a test strip
inserted. After the test strip is processed, the correct exposure
is read off for each of the three tri-colour filters. Next, the
diffuser is removed and the actual exposure made through each
of the three filters in turn. Processing requires only two solutions
(developer and bleach fix) and a temperature range of 65F to
85F (18-30C) is acceptable with the developing time increasing
from two to four minutes as the temperature falls across this
range. (Note: the 'Colour Photography' reviewer was critical
of Paterson for giving the impression of such a wide temperature
latitude, saying that it could lead to colour variations and
suggesting the user would do best to keep the temperature as
near as possible to 68F). Bleach fix immersion time is two minutes." |