Split grade printing: the key to success

[Nicholas Lindan]

There is a new application note on split-grade printing on the Darkroom Automation web site.
http://www.darkroomautomation.com/support/appnotesgmeasured.pdf

The article stresses that the key point in getting split grade printing to work is the necessity of treating high contrast prints differently from low contrast prints.

In this context high contrast prints are those made with a longer #5 exposure, and low contrast prints are those made with a longer #00 exposure.

When split grade printing in the traditional 2-test strip method:

• High contrast prints must be made with the black-point/high contrast test strip made first.
• Low contrast prints must be made with the white-point/low contrast test strip made first.

The article gives detailed information on split grade printing with a meter. It presents a simplified approach in which a simple graph gives you all the information you need to find the correct filter ratio. The complete contrast response of a VC paper - over all filtration settings - can be found with just three prints of a step wedge.

 

[ic-racer]

Looks like a well thought out system.

I agree with you 100% on the pros/cons of split grade. Especially #1 "Only works with prints with pure whites/highlights and blacks." I recall last year when I was starting split-grade, I saw an exhibit at the Cleveland museum (I believe from their own collection) and I specifically paid attention to blacks and white. Most prints did NOT have full black or white.

 

[ic-racer]

I was looking at your graphs and my own split grade graphs and realized that using this graph, you can make a SINGLE test print. Assuming you have the Darkroom Automation meter and stop timer.

Use the meter to get the density range of the projected image. Use this number to find the corresponding radial line on the graph. The radial lines are lines of equal contrast. Then guess at a time with which to set the 'stop timer' for the first test exposure sequence (either color first) and read the corresponding start time for the second color exposure sequence off the graph.

So, for a negative with a density range of 1.2 log, use the 120 ISO R radial line. Do the test strip with High contrast filter starting at, say 5 seconds (well, the graph would have to be re-done showing 'stops' ) and the Low contrast exposure sequence starting on 10 seconds (or the equivalent 'stop' exposure).

Of course this could be easily re-drawn to show "Stops" on the x and y axis. The lines of constant contrast are plotted as ISO(R) from the log density, which could easily be converted to "Stops" of density range. (ISO(R) divided by 30).

 

[ic-racer]

I was looking at your graphs and my own split grade graphs and realized that using this graph, you can make a SINGLE test print. Assuming you have the Darkroom Automation meter.

Use the meter to get the density range of the projected image. Use this number to find the corresponding radial line on the graph. The radial lines are lines of equal contrast. Then guess at a time with which to expose color (either color first) and read the corresponding start time for the second color exposure sequence off the graph. (Using a large step wedge overlay over the paper)

So, for a negative with a density range of 1.2 log, use the 120 ISO R radial line. Do the test strip with High contrast filter starting at, say 20 seconds and the Low contrast exposure sequence starting on 40 seconds.

Of course this could be easily re-drawn to show "Stops" on the x and y axis. The lines of constant contrast are plotted as ISO(R) from the log density, which could easily be converted to "Stops" of density range. (ISO(R) divided by 30). Though, I see the Darkroom Automation meter will show both stops and density. I see that it is only $94. Its on my 'want list'

 

[Nicholas Lindan]

I was looking at your graphs and my own split grade graphs and realized that using this graph, you can make a SINGLE test print. Assuming you have the Darkroom Automation meter.

Actually, the purpose of the meter and the application note was to do split grade printing with NO test prints.

You meter the negative contrast - from the graph this directly gives the ratio of filtered exposures.

The key point in the system is that low and high contrast prints are treated in different, though symmetric, fashion.

If the #5 filter exposure predominates (low contrast negative/high contrast print) then expose with the #5 filter for the metered shadow exposure. The #00 filter exposure is less by the filter ratio.

If the #00 filter exposure predominates (high contrast negative/low contrast print) then expose with the #00 filter for the metered highlight exposure. The #5 filter exposure is less by the filter ratio.

Thats it. No test prints. One chart. Of course you can do the same thing with the meter and graded filters and save a lot of palaver.

The downside to split grade is, as you have mentioned, that there is no direct placing of any mid-tones or mid-tone contrast, and mid-tones are really where the image interest lies and printing control should reside.

The upside to this method of split grade is that charts can be developed for any paper with 3 shots of a step tablet.
But that upside is only because the system's only information on a paper's response are its black and white points.

This method reinforces the anecdotal posting on APUG that for printers making the low contrast test strip first for the highlights find that split grade only works well for them when printing contrasty negatives. On can only assume those who find it works, and make the black test strip first, normally have low contrast negatives. Those who find it works either way make normal contrast negatives, and could save themselves a lot of bother by printing with no filtration at all.

So, for a negative with a density range of 1.2 log, use the 120 ISO R radial line. Do the test strip with High contrast filter starting at, say 20 seconds and the Low contrast exposure sequence starting on 40 seconds.

Hmmm. For under-lens Ilford filters with a PH212 bulb/condenser light source, equal exposures with #00 and #5 filters give a 3.8 stop / 1.14 log / 114 ISO (close enough to 120 for government work) contrast.

Of course, with a color head, that ratio is going to be different as the full-yellow and full-magenta filter settings are going to have different filter efficiencies from the Ilford filters.

The 2:1 ratio for soft/hard exposures for normal grade with a color head makes sense if one assumes Ilford added 1 stop of ND to the #5 high contrast filters, which they may have done to keep the printing times for the highest contrast grades at 2x the softer grades. If the same amound of ND was dialed into a color head for the magenta exposure then equal exposures would give a normal density print.

 

[Dan Henderson]

Nicholas: I am confused over your repeated references to low contrast negative/high contrast print, or vice versa. Is that meant to mean that if one has a negative with a density range that produces a lower contrast print than desired with no filtration, or perhaps equal low/high filtration, one would expose through the high contrast filter first, but with the low contrast filter first if the opposite were true?

 

[titrisol]

Ralph Lambrecht (darkroom magic) had a guide like that to be used with the Ilford EM10 enlarging meter. I found that you simply expose using the #5 filter to make the blacks black, and then with the #0 filter (I have no 0000) for the midtone (by experience)

 

[Nicholas Lindan]

I found that you simply expose using the #5 filter to make the blacks black, and then with the #0 filter (I have no 0000) for the midtone (by experience)

Now, try that with a really contrasty negative and I think you will find it doesn't work as well - and that doing the #0...0 exposure first and then determining the black exposure gives a more controllable result.

The idea that the printing technique needs to change depending on the printing contrast is briefly mentioned in Beyond Monochrome but then seems to be dropped from the subsequent examples and advanced techniques. The book also does not specify the dividing line. It isn't really a sharp demarcation but a region between -1 and 0 on the graph below. However, an arbitrary point at equal filtration works well enough.

I think this point is the key to getting split grade to work, and is the reason that many people find 'it works about 1/2 the time'.

There are many ways to skin a cat and even more ways to make a very good print. Some are better than others for some people. There is no magic path, and the application note certainly isn't pretending to be THE METHOD, it's just one method among many, and one that some printers may find useful and fitting to their temprement.

 

[Nicholas Lindan]

Nicholas: I am confused over your repeated references to low contrast negative/high contrast print, or vice versa.

Low contrast negative: flat, mushy, grey on grey ...
So a high contrast print (one made with high contrast filtration or paper grade) and a low contrast negative make a finished photograph with normal contrast.

You are right, it does seem a bit confusing in retrospect: "high contrast printing technique" might be a better term. "High contrast print" in this context doesn't mean the finished print is high contrast. Of course, you can make a high contrast print from any negative - it's the printing technique that matters, not the negative contrast.

And vice-versa.

Thanks for pointing it out.

 

[ic-racer]

Actually, the purpose of the meter and the application note was to do split grade printing with NO test prints.

You meter the negative contrast - from the graph this directly gives the ratio of filtered exposures.

Duh... Now I see!! For some reason I was interpreting the method as placing the large step wedge on the paper when making the exposure...Never mind...

Hmmm. For under-lens Ilford filters with a PH212 bulb/condenser light source, equal exposures with #00 and #5 filters give a 3.8 stop / 1.14 log / 114 ISO (close enough to 120 for government work) contrast.

Good pickup on that graph. That graph I posted is actually for a bare W45 Aristo, therefore somewhat distorted, compared to other light sources.

 

[mikebarger]

All the graphs and colored lines make me dizzy. Guess that's why I like Fred Picker for film exposure and Les for printing.

Pretty basic, even if you eat up a couple of sheets of film or paper.

Mike

 

[ic-racer]

So, just to clarify for myself. When using the meter, the actual print exposure sequence (high first, or low first) is irrelevant, but the way you METER the NEGATIVE ( low point vs. high point) depends on the overall contrast and anticipated high-contrast, vs low-contrast exposure bias. Is that right?

 

[Nicholas Lindan]

All the graphs and colored lines make me dizzy.

You can get them in black and white ...

The graphs and such are only of interest to people making metered exposures, though IC's will help you keep a tone constant as you change the filtration.

The point of interest for both gear-heads and touchy-feely-test-strippers is that the conventional advice given in this forum and in several web sites and books to "find the white point first" is wrong - well, wrong half the time.

If you are printing a flat negative you need to find the black point first, using the high contrast filter.

One conclusion I can draw is that the pundits over-develop their negatives. You may want to take the conventional 'film developing wisdom' from the same sources with a grain of sulfite.

 

[Nicholas Lindan]

So, just to clarify for myself. When using the meter, the actual print exposure sequence (high first, or low first) is irrelevant, but the way you METER the NEGATIVE ( low point vs. high point) depends on the overall contrast and anticipated high-contrast, vs low-contrast exposure bias. Is that right?

Correct.

Obviously you can turn the metering system inside out, but it is much simpler to do it in the manner presented.

When using test strips the whole premise of split grade printing falls apart if the test strips are made in the wrong order. Obviously, the order used in making the final print is irrelevant.

Split grade printing with a meter makes little sense as the meter will indicate the right grade of contrast off the bat so there is no need to go through the split-grade rigmarole. However, there are meter users who are adamant about using split grade ... customer is always right and all that ... so the note describe how you would do it using a meter.

Two things fell out in putting together the application note: the first was that the order exposures were determined mattered - and this was more critical to test strip printers than meter users; the second was that the whole spectrum of VC paper behavior WRT split grade printing could be characterized by making only three test prints - two if one wasn't being too critical.

Split grade, therefore, has an advantage to meter users because it allows fast and easy paper characterization. And paper characterization is the bane of meter users. If split grade results are 'good enough', then it is a technique that has some validity to meter users.

 

[mikebarger]

I think in Les' book it says his process works better with high contrast negatives.

I think the goal is to fine tune each step to get you to the print you want/like.

As you have stated, there are many paths to that goal.

Mike

 

[Mahler_one]

To some degree I agree with Mike. From reading the interesting and varied opinions on this current discussion thread it has become readily apparent that there are those who prints are guided mainly by the visual appearance of test strips, and others who use meters and charts in order to hone in on the appearance of the print that they visualize. Neither one is, of course, wrong or right. However, split grade printing has appealed to many because of the relatively simple approach offered in which it is not necessary to really know the absolute grades of filtration that one can achieve, nor is it important to have done any serious standardization of materials searching for exposure correction depending upon filtration grades, etc. One makes two test strips based upon either F stop timing or more prosaic timing in seconds. Burning in or dodging can be approached while using either the contrast printer or the highlight printer, and the print is completed with a result which reflects the experience and expertise of the operator. Certainly Nick's advice concerning the order of the test strip is original, and very interesting.

I admit to also being interested regarding the possibility of mid tones being somewhat neglected ( my word, not his ) in split grade printing as written in Nick's learned and excellent article which was referenced here. I don't quite understand why such is the case in split grade printing. Certainly we have all seen excellent examples of prints made using the split grade technique. While such examples might have been examined on line where mid tones might not be very obvious ( on our monitors ) I have not heard of such "mid-tone neglect" ( once again, my words and not Nick's ) before. If Les is any where is sight, I wonder if he might have the opportunity to comment. I am not trying to initiate an argument amongst friends and colleagues, but certainly comments from very experienced split grade printers would be most welcomed. I do recall reading comments by the late Mr. Davis, and referenced by Howard Bond and many others, in that split grade printing accomplishes nothing that more "conventional" printing cannot. Importantly, I do not recall reading (until now) the converse, i.e., that more conventional printing can accomplish something that split grade printing cannot ( better mid-tones ), i.e., using a combination of filters, one can achieve a look in the mid tones of a print that split grade printing "cannot" produce. Hence my interest. I hope I have not misinterpred Nick's remarks, and if so, I apologize for my errors.


Ed

 

[Nicholas Lindan]

Mid-tones are there in a split-grade print as much as they are in any other print.

What split grade gives up is direct control over mid-tones.

If you are making a portrait in the conventional manner you would make a test strip print of the face and control the exposure and contrast for the face. If metering, ditto - meter for flesh tones and facial shadows. After getting the flesh tones and face contrast as one would like then one burns and dodges as needed to get the non-important shadows and highlights in order.

With traditional split-grade one determines exposure and contrast based on highlights and shadows - where the midtones end up is a matter of luck. Often a second adjustment may be needed. Dodging and burning then concentrate on getting the midtones into line.

An advantage of split grade is that one can leave the highlight exposure rather week and then burn-in the highlights with the high contrast filter. This is especially useful if the highlights are in the shoulder of the film curve and need extra contrast to get them to show detail. Ditto shadows, and ditto doing the obverse to suppress detail or distracting specular reflections.

Some people do a rather odd combination of making a low contrast exposure, judging the middle of the tonal range and then adding high contrast. I imagine they have developed a 'feel' for the method and can anticipate what they are going to get. I don't see any advantage over taking a guess at the right contrast grade, making a test print and then adjusting the contrast grade as needed. And I don't see any advantage over simply metering the midtones and being done with it.

The end result is (or can be) the same in all cases. Use the method that works for you - that's why God invented more than one method - though more likely God couldn't make up his mind either.

It is always good to know more than one way to get to the print you want. Sometimes you can't get any headway, and trying another method that approaches the problem from a different angle may yield success.

As far as advantages to graded filters Vs split grade - apart from the obvious ones of speed, convenience, reliability, direct control of any tone, direct control of any contrast range - I only know of a theoretical one. Modern VC emulsions are made from three components with green, cyan and blue sensitive (well, they are all sensitive to blue) emulsions. The cyan emulsion lets the manufacturer smooth out the bumps in the HD curves of the lower contrast grades. As contrast increases the cyan emulsion exposure must be kept between the blue and green. With graded filters it is possible to design the filter to allow fine control of the cyan emulsion. Obviously, with only two exposure wavelengths in split grade printing it is impossible to provide individual control of three emulsions - a third exposure through a cyan filter would be needed. However, it seems that Ilford, at least, has designed their paper so that the cyan emulsion is well behaved in split grade printing, and any advantage seems moot.

Obviously, though I try to see all sides (cough), I am not a great fan of split-grade. I find using an exposure meter in the darkroom to be just as natural as using one in the field and don't see how the use of one in any context lowers from the 'art'. People seem to think they need an excuse or reason not to change their ways - as far as I am concerned 'I don't want to' is the only one that counts. Who can argue with "I don't like brocolli."

De Gustibus non est disputandum.

 

[John W]

Split grade printing with a meter makes little sense as the meter will indicate the right grade of contrast off the bat so there is no need to go through the split-grade rigmarole. However, there are meter users who are adamant about using split grade

To this point, I'll refer to Tim Rudman in the recent (there was a url link here which no longer exists):

Split grading though allows you to also D & B (more importantly D) during the G 00 or G 5 thus altering local contrast as well as density. It also allows you to confine creative techniques like soft focus filters, texture screens. etc to just one of the filtered exposures. This can be pretty useful.

I'll also observe that the correct grade may not be available if the printer is using a filter pack (discrete filter steps) instead of an enlarger head offering continuous VC filter control.

 

[Mahler_one]

Thanks Nick. Well understood. Both paths lead to the same place of course. I appreciate your taking the time to post your original article, and answer the numerous questions concerning both the article, and the use of the meter in split grade printing.

Ed

 

[ic-racer]

Control over the mid tones (and overall print intensity) is so important in my method of working. That is why I created that graph that I posted earlier in the thread. Mid tones are set with the test strip, then contrast is altered as needed by moving along the curved line and reading the resulting new exposure times. When I work with my chart it eliminates any problems associated with a system that bases everything on a maximum black or a maximum white.

 

[Nicholas Lindan]

Control over the mid tones is so important in my method of working. That is why I created that graph that I posted earlier

The standard 'paper speed charts' supplied by Darkroom Automation provide the same service for graded filter users.

http://www.darkroomautomation.com/support/mgivrcpaperspeeds.pdf

For each standard Zone system tone the chart shows the exposure required for each grade of contrast. If you want to go from a grade 2 1/2 to 3 1/2 and maintain a constant Zone III shadow tone you would reduce the exposure by 0.3 stops. If, with the same contrast move, you wanted to maintain Zone VI (skin tone) you would add 0.1 stops.

To use the chart you find the paper grade you are using and the desired tone - at the intersection of the row and the column you find the paper speed.

• To move the same tone to a different grade of paper you move horizontally to the new paper contrast column and apply the difference in paper speeds.
• To move a specified tone to another tone, using the same grade of paper, you move up and down the column to find the desired tone and again apply the difference in paper speeds.

You make the most bizarre moves with the chart. To move a Zone VII highlight on Grade #00 to a Zone III shadow on Grade #5 you would add 2.8 stops of exposure when changing to a #5 filter. And you can predict that the Zone VIII highlight in the original will transfer to a skin tone on grade #5.

You can use the chart without needing a meter or f-stop timer. The time changes are in stops, but a stops->seconds chart or f-stop dial face will serve for those who insist on thinking linearly.

It is possible to turn these paper speed charts into your graphical form. It is also possible to provide a chart for split-grade use, where instead of filter numbers at the top of the columns it would be #00/#5 exposure ratio.

 

[Ken N]

I've been successfully split-grade printing for a number of years now and I've got to admit to total confusion in trying to follow these charts and the general text of this discussion.

Use of split-grade has less to do with high-contrast vs. low-contrast negatives. For me, it has everything to do with the ability to control my high/mid values separately from the low values. This is, in effect, the darkroom equivalent to "adjusting gamma". For example, Kodak T400CN film had the nice high and mid-tone spread that I like, but when properly printed the blacks just were not there. By using split-grade, I can add the blacks to give the print a nice solid bottom-end without the mud. Other negs can be too brutal on the bottom end so it's just a matter of backing off the Grade-V exposure.

It honestly does not matter which exposure you do first as long as you are consistent. I use the RH Designs gear and split-grade printing is a breeze with it, but it is preferred that you always work the same way. It's too easy to make mistakes in the darkroom and by standardizing on only one way (soft then hard) it minimizes unwanted trashcan filling.

 

[Nicholas Lindan]

by standardizing on only one way (soft then hard) it minimizes unwanted trashcan filling.

I think you are saying that it does make a difference, as if you do it the other way round your trashcan overfloweth - though maybe not for the same reason.

That it makes a difference has been the gist of the whole thread.

If you make prints at the equivalent of grade #2 or softer then making the test strips soft then hard is the correct way to go.

If you make prints at the equivalent of grade #3 1/2 or harder then the results of the test strip exposure will be more accurate if you do it the other way round and make the tests hard then soft.

If you make them in the #2 1/2 - #3 range it doesn't much matter which way round you work.

However the method of determining which test print to make first, as described in the application note, produces very accurate results, achievable by the greenest of printers - absolutely no experience needed to get it right the first time and every time.

This isn't a debatable point ... it's the physics of the thing and there is no way around it. It's not a terribly original point either, see Way Beyond Monochrome bottom page 80, top of page 81. I know that free advice on the internet can not possibly be worth anything, so you can go to a bookstore and pay $49.95 for the book and then the same advice will be of value.*

The application note goes beyond the Beyond of Monochrome by putting hard quantitative measurements on the dividing line between hard and soft techniques.

Printers who have been working with split grade for years and are fans of soft-then-hard know that if they have a very soft negative that they should underexpose the soft exposure by 1/2 to 1 stop or so because the very strong hard exposure that will be required will effect the highlights.

There is no debate that someone can print their whole life, producing gorgeous prints, using a completely different method. If you do anything long enough you end up doing it by feel.

If an analytical approach doesn't suit your temperament, then for heaven's sake don't use it.

For those whose temperament it fits, an analytical approach gets to a realization of one's artistic vision by a more direct path.

* You can read this chapter for free at Google Books Way Beyond Monochrome but you should probably send Ralph Lambrecht and Chris Woodhouse a check. The "Advanced Techniques" chapter, following, points out some of the advantages of being given the opportunity in splitgrade to burn and dodge with the filter extremes. Chris Woodhouse holds the patent on the RH designs timer.

 

[Ken N]

Interesting observations, Nicholas. I will admit that I restrict my split-grade printing to Grade-00 and Grade-5 filters. As such, the Grade-5 exposure rarely affects the highlights. (if it is, then you aren't getting a clean Grade-5 or your Grade-00 is slightly overexposed). Using the dichromatic filters in a colorhead enlarger tops out at about Grade-4). When using different filters, things get more difficult to predict because you can't do a test strip on one of the exposures as the second exposure will end up screwing up what you're looking at.

I've "calibrated" my methodology to the use the split-grade feature of the StopClock Professional. The ZoneMaster II gives me my recommended paper grade and I have a given start-point with the StopClock which then also tells me my effective paper-grade when using 00/5 filters.

Sorry, I don't mean to namedrop a competitor here, but this is what I use and it happens to work for me. You also have an excellent product and can be used in the same or similar manner. I have read a lot of Chris' writings on split-grade printing and have nothing but the highest regard for his recommendations. One thing he recommended several years ago was sticking with a uniform approach and that approach works equally well for soft negs or hard negs. I found no reason to alter methodology because if you have to alter it, then the methodology is flawed.

However, I note that in WBM, that Chris does recommend using the Grade-V exposure to determine your start point on certain types of images. Oh well...

 

[Nicholas Lindan]

If you look at the HD curves for the toe region, you can see the shift at the 0.1 OD point as the relative high contrast exposure is increased.

This is with #00 and #5 Ilford VC filters, PH212 bulb condenser light source. As 'clean' a #5 as one would like.

It shows the hard exposure will effect the highlights if it gets above the soft exposure.

If you do the test strip for the highlights then you put down the violet L3 H-4 curve first (high contrast is 4 stops down, or 1/16th of the low contrast - close enough to all low contrast for this discussion). If the following high contrast exposure is equal or less to the low contrast exposure (L3 H-4 to L3 H-1) then there is no shift in the highlight. If the following high contrast exposure is greater than the low contrast exposure (L3 H+1 to L3 H+3) then the highlight shifts - and what was a 0.1 density highlight becomes a 0.3 light gray for the case of L3 H+2 (high contrast 2 stops over (or 4x) the low contrast exposure).

As to fixed methodologies: "To a man who has only a hammer, everything looks like a nail."