Split grade printing question

[Ian C]

The following applies to the dyed Ilford Multigrade variable-contrast filters.

The use of dichroic filters, those intended for color printing, and those in variable-contrast printing heads might behave quite differently.

Using two equal, sequential exposures, one with a low-range filter, such as grade 0, and the second with a high-range filter, such as grade 5 will fail to give the average grade, 2.5.

Excerpted from the instructions accompanying my Ilford below-the-lens MG filter kit:

“Exposure

MULTIGRADE filters are very easy to use; no complicated calculations are needed when changing from one filter to another. The filters have the following relative exposures:

Filters 00-3 ½ Ful speed (x1)
Filters 4-5 Half speed (x2)”

The high-range filters require twice as much exposure as the low-range filters to obtain the same developed print density. With this in mind, to get the midpoint contrast, grade 2.5, with sequential exposures with grades 0 and 5 filters, the grade 5 exposure must be double that of the grade 0 exposure.

For example, if we make a 20-second grade 2.5 print (at a fixed aperture) with a grade 2.5 filter and wish to duplicate it with two sequential exposures using a grade 0 filter and a grade 5 filter, the exposures would be

10 seconds at grade 0 and 20 seconds at grade 5.

A print made with equal exposures with grade 0 and grade 5 filters would have less contrast than the average (grade 2.5). The contrast would be roughly grade 1.7. Both exposures would have to be increased to give the desired density. Otherwise the print would be underexposed by about 0.42 stops.

 

[Lachlan Young]

Thanks Lachlan.
Burning in without dichroic filter is in fact burning on grade 2. It has advantage only of gaining around 1 stop comparing with equivalent filters. Now we are back to the first point!
What's exactly the difference in the print or in the method capability, between direct and split grade printing?

I do not think post flash will be easy. Could you Lachlan explain it?
As far as I understand, the only advantage that usually and repeatedly explained with split grade printing over direct, is easier dodging/burning in.
But, even the beginner printers know that they should burn in with lower grade filters after direct printing on the optimal grade for overall contrast, but that does not "technically" make the whole process split grade, though "effectively" it is.
This 5 pages PDF link has a very useful information(click the underlined text or the link):
http://www.berk-edu.com/BAS_subsite/PDF_bas/SplitFiltration2b.pdf
This technique works well with negatives "that" are relatively flat (not contrasty) with lots of texture and detail.
It looks that split grade is only for easier negatives.
When studying the results and comparison on page 4, anybody can realize that split grade technique is much sophisticated than the achievement.
Could not understand why the comparison was not done with grade 2.5 at little more exposure direct print, for example?

I'm not terribly interested in the pro or con of split-grade, especially given its repeated promotion as a pointlessly lauded 'magic' answer to fundamentally inept printing technique. I'm much more interested in the idea of using a 47b & masks etc to optimise the apparent sharpness of a neg.

MG paper is multiple G5 emulsions of different speeds & colour sensitivity, and hitting it with an extra burst of unfiltered light will give the biggest kick to the fastest (thus 'softest'), especially when it's already in a state of excitation following an initial exposure, at least as I understand it. Leaving the neg in the enlarger is not perfect, but it is a very handy tool to have on hand when setting up a post-flash would be a waste of time.

If you don't have or want a second enlarger, Secondhand Darkroom sell the RH Designs paper flasher which might be more convenient for some. Main thing is that you need a decent sense of print geography if you're going to use the white light to a level over the paper's threshold (dodged & burnt) to help any awkward highlights. None of this is difficult to learn - using it creatively is a different matter - even so, it takes less time to try than it does to write about.

 

[CMoore]

1. I simply need more experience with it.
2. I need to try the slide-in filters.....not the knobs on my Beseler 45 color head. Don't think it will necessarily be "better"..... but it should at least be different.

 

[MattKing]

I'm not terribly interested in the pro or con of split-grade, especially given its repeated promotion as a pointlessly lauded 'magic' answer to fundamentally inept printing technique.

I resemble that !
I find split grade printing to be a really powerful and flexible tool.
But most importantly, I think it forces people to pay attention to some of the things that they benefit from paying attention to.
And I almost never use it without using burns and dodges with different contrast settings.

 

[CMoore]

And I almost never use it without using burns and dodges with different contrast settings.

OK.....i am not TRYING to complicate this, but let me ask.
Just for example, are you saying that you might do 15 seconds at Zero...6 seconds at Five, and then burn something at filter 3.5 for a few seconds.
Or are you saying 15 at Zero...6 at Five, and then part of the photo at Zero for another 10 seconds.....if you know what i mean.?
When you go back and burn, is it with the same filtration that you used for "The Split".......or do you switch to a third filter.?
Thank You

 

[MattKing]

OK.....i am not TRYING to complicate this, but let me ask.
Just for example, are you saying that you might do 15 seconds at Zero...6 seconds at Five, and then burn something at filter 3.5 for a few seconds.
Or are you saying 15 at Zero...6 at Five, and then part of the photo at Zero for another 10 seconds.....if you know what i mean.?
When you go back and burn, is it with the same filtration that you used for "The Split".......or do you switch to a third filter.?
Thank You

All of the above.
If a print is straightforward and the contrast is fairly even throughout the important parts of the image, I may not use split grade printing at all. Something like a straight print at a particular single contrast, with maybe a bit of burning and dodging to taste.
But for a significant number of prints, once I evaluate the straight print, I'll come to a decision that different parts of the scene need both different exposure and different contrast. So you end up sketching out which parts of the image require different amounts of low contrast and high contrast filtered exposure.
I have an older Ilford Multigrade 400 light source, so changing filtration and changing timing is accomplished by pressing contrast buttons and turning rotary time dials on a control unit, but I've certainly done the same with rotary dials on a colour head.
Here is an example of what was fairly close to a straight print - no split grade required. Note how the textures are subtle and the light was both diffused and directional:

And here is a print that needed all sorts of split grade choices and manipulations. Note how the textures are dramatic, and the light is both directional and contrasty:

 

[ic-racer]

For simplicity, as posted previously, one can base image exposure on a single mixed-light exposure. Dodge as usual and burn with white light. No 'need' for the split exposures (but one can get the same results with the added complexity of split exposures if on wants).
For example the older Ilford filters used 'white' light as the 'soft' grade. So, in that system, the 'soft' WAS white light. And, as posted previously, white tungsten light has more green than blue.

It is up to the one printing to determine the complexity of the printing system.

KISS: Base exposure with mixed blue/green light. Dodge with black, burn with white.

 

[Pieter12]

I have become addicted to split-grade printing. However some prints come out a bit flat and dingy. I assume the problem is the 00 exposure. My question (because I won't get back to the darkroom until the weekend) is when I reduce the 00 exposure, should I compensate by adding to the 5 exposure to keep the dmax? I will experiment this weekend but would like a head start in this matter.

I found the answer to my question on the Large Format forum. "For split grade printing when you shorten 1s the exposure with the 00 filter then you extend 2 seconds the exposure with the 5 filter, because the 4, 4.5 and 5 filters require 2x more time..."

Going to the darkroom now.

 

[cowanw]

It may be that not all enlargers have the same power of illumination in both colour channels. As an example my green/blue Zone VI is much more powerful in the blue than the green and a rule of thumb such as suggested is way off. YMMV

 

[MattKing]

Those speed measurements are keyed to a particular near highlight tone. If you are trying to match to another tone, that suggestion may not work.

 

[Pieter12]

It may be that not all enlargers have the same power of illumination in both colour channels. As an example my green/blue Zone VI is much more powerful in the blue than the green and a rule of thumb such as suggested is way off. YMMV

Yeah but I am not using a color or multigrade head.

 

[Pieter12]

Those speed measurements are keyed to a particular near highlight tone. If you are trying to match to another tone, that suggestion may not work.

Those speed measurements are keyed to a particular near highlight tone. If you are trying to match to another tone, that suggestion may not work.

Yes, but it is the closest anyone has come to answering my question. At least it is a jumping-off point.