De Vere 504 & split-grade printing?

[koraks]

this Les McLean article on split grade printing very helpful: https://www.lesmcleanphotography.com/articles.php?page=full&article=21

That's an excellent resource.

I'll be happy to try both side by side and report back

That would be most interesting, thanks!

 

[cowanw]

What may distinguish the "Ilford Way" from others is the beginning of the process where both Ilford presenters, Dave Butcher and Rachel Brewster both say that your first test print should be made at grade 2.5 from which you choose the best exposure. From this test print at grade 2.5 you divide that best time in half and use half of the time at 0 or 00 and half at grade 5

Everybody learns differently and its all good. My Zone Vl has a compensating timer and I find that the blue light exposure clips along like a thoroughbred and the green light timer clops along like a Clydesdale, easily twice as long when set to the same "time"
My suspicion is that the blue light is more "efficient" but it may be unique to my enlarger. As always everybody's work flow is different and each must work out what seems best for themselves.

 

[pentaxuser]

Everybody learns differently and its all good. My Zone Vl has a compensating timer and I find that the blue light exposure clips along like a thoroughbred and the green light timer clops along like a Clydesdale, easily twice as long when set to the same "time"
My suspicion is that the blue light is more "efficient" but it may be unique to my enlarger. As always everybody's work flow is different and each must work out what seems best for themselves.

Yes you may well be right if using what I assume to be blue and green lights. The person in question, Dave Butcher, was using a Durst with a halogen bulb and Ilford MG filters. This may make a "rule of thumb" method of splitting the best exposure time for the 2.5 print OK for a one bulb enlarger and MG filters but I don't know. Even then he decided to alter time slightly for the grade 5 exposure and the actual low grade filter used from 0 to 1

Interesting or otherwise, Les McLean's method appears to be in some ways simpler and produces what appears to be a good result Anything else may be unnecessary tinkering

pentaxuser

 

[albada]

Split-grade printing is based on an approximation -- an approximation that is poor in some common situations. Here's a paragraph @Nicholas Lindan wrote in an app-note for split-grade:

Traditional split grade printing is based on the naive assumption that the black and white points can be controlled independently with the high and low contrast filters. This, however, is only true for prints made at close to normal contrast with roughly equal amounts of high and low contrast filtration - a grade 2 print - which beggars the point of why bother with split grade at all if it only works at one grade. Some pundits favor always making the high contrast test print first and some the other way round - followed by lot of hand waving and assurances that experience will allow the printer to modify the result of the test prints as needed - but this again negates split grade printing’s promise that it will find exactly the right contrast grade for a negative and that experience is not required.​

​

The key to making split grade printing work reliably is realizing that high and low contrast prints​

must be treated differently.​

Here's the link to this app-note: Split-Grade Printing: A Measured Approach.

This app-note describes a method of split-grade printing using his easel-meter (it's for sale, and I own one) and no test-strips. The method requires taking two meter-readings, so I suspect you could create two test-strips in lieu of the two readings. Then you should obtain the desired highlights and shadows more reliably.
I wrote "should" because I have not tried this method because I programmed the equations into my LED-controller based on meter-readings.

Mark

 

[ic-racer]

In this example (from my darkroom), a 90 second Green exposure gives the same mid-tone print density as a 45 second blue exposure.

The table shows, for example to increase print contrast from, say ISO(R) = 70 to ISO(R) = 105, the exposure would need to change from:
Blue = 85 sec; Green = 20 sec, to Blue = 58 sec; Green = 58 sec, etc, etc...