I have written a few posts on split-grade printing before (here and here) but I thought that I would revisit it again in more detail. The reason for this is that I am having some problems with it, so a post like this forces me to re-evaluate what I am doing, starting with the basics and trying to understand where I am going wrong.
What is split-grade printing?
As the name suggests a split grade print is one where the print has been made up from two or more contrast grades. To explain…
Many modern papers are ‘variable-contrast’ (VC) which means that you can opt to modify the contrast of a print, say from soft to hard, without changing the paper.
Before variable contrast papers became available printing papers produced a single print contrast. Contrast selection could be achieved in a variety of ways. The simplest method was to change the paper to a softer or a harder version. This meant keeping a stock of papers in all the contrast grades, an expensive option.
Contrast control techniques were developed in order to meet various challenges that the printer came across, often to salvage prints from poorly exposed negatives 1. These techniques are still used but some can be finicky and time-consuming. They help the printer to control the overall exposure of the print, but they are less helpful in dealing with local contrast issues within one photograph.
This is where VC papers come in. You can choose to print areas of differing contrast in the same photograph. To change the contrast within one photograph you simply use the appropriate colour filter for a particular contrast (or dial in the appropriate adjustment on a colour enlarger head). You expose the paper for some of the time under one filter (grade), then you use a different filter (grade) for the remainder of the exposure time. This is what we mean by ‘split-grade printing’.
This full split grade printing route can be overkill for many situations, since it takes more effort and needs more judgement than single grade printing. There is a slimmed down version of split grade printing that is often sufficient for the job in hand but more on this later.
Why use split-grade printing?
When we come to print pictures from a negative we have already made decisions that bind us to a particular contrast. For example the way we metered the scene, the choice of film developer, the film development time allowed and the amount of development agitation will all determine the overall contrast you end up with. This contrast may be acceptable but you may still want to alter the contrast in selected areas. Altering the contrast means affecting the dark tones more that the light tones, or vice versa 2.
For example let’s say that you are printing a high contrast negative of some trees against a sky on a softer grade so that you capture some of the highlight tones in the sky. The mid-tones can appear to be muddy (lack of tonal gradations) and the shadows may also lack separations between black, dark grey and light grey. Burning in the sky may be tricky if tree branches overlap the sky areas. Dodging the shadows may not help as the problem is the local contrast, not the overall exposure 3.
With split-grade printing we can boost the detail in the highlights without affecting the shadows and we can bring out the shadow details without blowing out the highlights of that area.
Printing with two exposures, each with a different contrast grade lets us print the picture as if adding layers (using a photoshop metaphor). This metaphor is not far fetched since the paper’s emulsions are laid down in layers. One layer is sensitive to blue light and produces a hard contrast. Another layer is sensitive to green light and produces a softer contrast. Blue light affects darker areas more than light ones. Conversely green light affects lighter areas more than dark ones. Varying the proportion of the print exposure to green and blue light alters the contrast. Selective burning and dodging under a specific filter lets us control the contrast in a specific area 4.
I am guilty of labouring the point. The key principle is that selective burning or dodging with blue and green light gives us a great deal of control over how the photograph will look.
The split-grade printing process
The various books and on-line articles that cover split-grade printing describe varying approaches that can make the process seem complicated. Some articles contradict each other. So I have learnt that the only fool-proof way of getting something right is to rely on advice from people who have worked at it for a long time or to experiment and make mistakes yourself. Most of the advice on the web seems to regurgitate unchallenged assumptions.
Here I describe the approach that I take and the difficulties that I encounter.
The starting point is to decide on a plan after looking carefully at the potential of the image from the contact sheet through a loupe. I do my contact sheets on a soft contrast setting so that I can capture as much detail as possible in the highlight and shadow areas. Contact sheets on a grade 2 or a harder setting may not show sufficient information in the highlights and shadows.
I can’t over-emphasise how important it is to have a plan for the picture from the outset. It will determine a number of steps further on in the process.
I then make a decision as to two different printing approaches 5:
- The ‘quick’ method where the basic exposure is made at one grade (say 2) then burning in the highlights at a different grade. The shadows can also be dodged then burned in at a different grade.
- Exposing the paper using two different grades, dodging where necessary, then burning in with different grades.
The choice of method depends on how fundamental a change is required. Most of the time if I have got the basic negative exposure and development right, I would opt for the former option 6. Having to often resort to the second approach might suggest the need to re-examine basic film exposure and development techniques 7.
If I opt for the second method, then another choice opens up:
If I’m interested in the highlights as the defining characteristic of the picture I will start with test strips and print plan involving the highlights first. If the shadow details are the most important factors that make the picture, then I start with those.
Here is an example I have been working on. The first stage is to develop a plan.
We have a diagonal line of trees and a focal point where this line intersects with the horizon in area ‘A’. My intention is to provide some depth to the tree line by having the trees on the left darker than the trees that recede into the picture. The area A is to be lighter than the rest of the sky to draw the eye in and the sky is to have some texture. Finally the tram-lines ‘1’ and ‘2’ are to be accentuated by being lighter in tone.
This print was done at grade 2 (Ilford MGWT) after a test strip to give me the earliest exposure time for black.
To print the picture one option would be to simply burn in the sky and dodge along the tram-lines and area A. The problem with this approach is that burning in the sky along the tree line is going to produce blackened branch tips and dodging along tramline ‘2’ will leave me with uneven tonality in the tree trunks.
I decided on a full split-grade approach.
As in single grade printing we start with taking test strips. For me, the highlights are what drive this picture so I opt to do the highlights first.
I placed the test strip on the sky along tramline 1. From this test strip at grade 0 I decided on an exposure of 13 seconds, bright but it shows some tonality in the sky. I see from the test strip that significant burning in of the sky will need probably 2 stops or more. I also see that additional brightening only requires a stop of a fifth.
The next test strip is at grade 5. I exposed the strip at grade 0 for 13 seconds then did my intervals with grade 5 in an area of the picture where I am looking for a deep grey, i.e. just off black.
I realise that it’s quite difficult to judge the shadow detail as the exposure intervals are parallel to the trees and my eyes find it difficult to pick out the zone edges (I’ve drawn them in here). So I retest using strip intervals that run at right angles to the trees:
This is easier to judge and I choose 14 seconds as my base grade 5 exposure time. I also see that my highlights are muddier than I would like. I assume that the grade 5 exposure has had a slight effect on the highlights, so I make a note to reduce the grade 0 exposure a little.
So here we come to my biggest area of difficulty: test strips - taking the right test strips. I have wasted a lot of paper and time as a result of getting the tests wrong and having to start again. Firstly, I tend to rush them. I don't always place the strips in the right place in the picture. For split-grade printing the grade 0 and grade 5 test strips need to be in areas where you want the result of the exposure to take effect - i.e. the visually important parts of the picture. In this case, the areas where the highlights and shadows play an important role. This is obvious I know, but it is contingent on having a plan for the picture as a whole. Secondly, even when I have selected the right areas for the test strips, I still find it difficult to select the right exposures. I think it just comes with plenty of practice. Finally, as already mentioned, the second exposure will have an effect on the results of the first exposure, so a small tweak is required. I don't find this easy to judge.
First Work Print
So the results of the test strips indicate exposures as follows: A grade 0 exposure for 13 seconds. I opt to reduce this to 12 seconds as my tweak. Then an exposure of 14 seconds at grade 5:
Not too bad a starting point. I have some tonality in the sky but have not had to burn this in to get it. The trees in the centre of the picture are just short of black.
Printing Plan and Print Maps
To put my picture plan into action I now need to have a printing plan. Here it is in terms of print maps:
My grade 0 exposure of 12 seconds is split into two exposures of 7 seconds and 5 seconds. In the first exposure (Figure 6), I dodge the foreground to bring out the contrast and a burn tramline 2 with a grade 5 burning tool to lighten the sky in the trees.
Figure 7 should give me the lighter tonality for the focus point.
Figure 8 should give me a little gradation in shadow tonality
Finally figure 9 should give me more depth to the sky without affecting the tree branches.
The final result:
In a comparison with the first work print you can see the following: greater texture in the sky, brighter focal point, brighter highlights in the sky through the trees and a gradation from black to very dark grey along the tree line to add depth. The differences are more apparent on the actual prints – something is lost in the scans.
Hopefully this long post demonstrates a little of the split-grade printing technique. I am still learning about it and making mistakes, particularly in placing and assessing the test strips. I also struggle with the small adjustment required in the effect of the second grade exposure on the first. If anyone has any suggestion on how to better overcome these problems please feel free to comment.
- These included altering the print exposure time to print development time (i.e the ratio), split tray development baths using hard and soft developers, print flashing, selective fogging, employing chemicals that differentially affect the development process in proportion to image density (the ‘Sterry’ process, which is similar in principle to what Bromoilists do), selenium intensification and so on ↩
- Altering both by the same amount, as in normal dodging or burning, does not lead to a change in contrast. ↩
- Adapted from an example in Ctein, ‘Post Exposure, Advanced Techniques for the Photographic Printer’, Butterworth-Heinnemann 1977 p 110. ↩
- The situation is more complicated than this. A more complete description can be found in Ralph W. Lambrecht and Chris Woodhouse, ‘Way Beyond Monochrome’, Focal Press 2nd Edition 2018, p.309. ↩
- I am grateful for the discussion in Eddie Ephraums, ‘Creative Elements, Landscape Photography – Darkroom Techniques’, Fountain Press, 200 p. 122 ↩
- I am most thankful to Andrew Sanderson, an Ilford Master Printer, who showed me this technique. ↩
- See Andrew Sanderson’s excellent blog on this. ↩