Taking that first jump, and wanting some reasoning behind this video

[Torquemada]

I still don't get it. Why does anyone need to use only two or four seconds of printing time? Haven't they ever heard of neutral density filters, or of combining all three, C,M,Y, on a colorhead to attain some neutral density? Heck, I've worked with enlarger light sources hundreds of times brighter than that toy thing in the video, and never needed to go below 10 seconds or so.

have a beseler chart that shows combinations that include all three colors in the mix? I only see for multi grade printing of black and white paper as single setting for yellow or magenta each. Or mixture of yellow and magenta.

Only time ive seen REFERENCE to use of the blue filter in a dichroic head was for COLOR prints.. and i havent seen much talk on those settings being applicable.

[Corran]

I pretty regularly use 3-5 second exposure lengths (with multiple exposures). If the length prevents easy burning or dodging I have a little device that lowers the output to the light by a percentage and I get the exposure to a good length for the print needs.

For example, I might have 6, 3-second exposure 'clicks' for a given print, with two of them needing dodging and then 3 needed for burning. If that's an issue I can set it to 50% output and use 6 second exposures.

I don't particularly like thick negatives. Some might see my negs and think they are a bit thin but I've found TMX to work better (for me) with thinner shadows than perhaps FP4.

[Drew Wiley]

Torq - when all three are mixed it creates neutral density. Then in ADDITION to that, you can selectively tweak filters for sake of VC paper contrast. I was stating that in relation to lowering the overall amount of light in order to increase exposure length.

And what on earth do blue filters by themselves have in common with color printing?

[Vaughan]

have a beseler chart that shows combinations that include all three colors in the mix? I only see for multi grade printing of black and white paper as single setting for yellow or magenta each. Or mixture of yellow and magenta.

Because variable contrast b+w paper is orthochromatic the red light doesn't matter and controlling it does nothing except make the image lighter or darker to our (panchromatic red-sensitive) eyes. The two-filter Y+M combination introduces neutral density because the yellow blocks a bit of blue light and magenta blocks a bit of green light.

[Peter Lewin]

Corran, what you describe in post #22 (multiple 3-5 second bursts) is the method Fred Picker taught me over 50 years ago, and which I have used ever since. He (and I) make test strips typically with 3 second intervals, count up to the strip we want, and print using “x” 3 second bursts. I also use his ZoneVI light head and timer, which allows me to dial down the brightness if otherwise I would need a much higher f-stop or end up with too short an overall exposure time.

[Vaughan]

... make test strips typically with 3 second intervals, count up to the strip we want, and print using “x” 3 second bursts.

Ah, that technique avoids (or takes into account) the intermittency effect. Having said that, I prefer to use continuous exposures but whatever works.

[Drew Wiley]

What is meant by a "burst"? Triggering an ordinary head every three second? - in that case, you're swamped with warm-up and afterglow issues unless there is a shutter in the light path. Xenon flash burst systems exist, and even fancy halogen ones with feedback loupes. But those options were way out of Fred Picker's league.

With colorheads, I recommend all three - CMY - to attain neutral density, even with VC papers. That's because there's always a certain amount of white light spillover getting past, and the less the better. It's a bigger problem with old colorheads rather than newer ones. I happen to have a couple RGB additive enlargers, but that's a different story.

[Corran]

I have two b&w enlarger heads, one condenser and one diffusion. The diffusion needs and has a heater to keep the bulb warm. Neither gives any issues with "warm-up" or "afterglow" and I've made hundreds if not thousands of prints now in my 10 years of darkroom printing. This technique was also taught to the college BFA students by a friend and mentor who was the photography professor at a large university, with equally normal results.

[Peter Lewin]

Drew: Semantics. I should have simply said a series of 3-second exposures. I used the word "burst" thinking of each exposure as a burst of light. As Vaughn said, Picker was avoiding any intermittency effects, and whether or not that is still an issue, the methodology has worked well for me.

[John Layton]

...extremely embarrassed here - having taught literally thousands of students, ages 5 to 81, elementary school through graduate (MA) level...what the heck is the "intermittency effect?" Perhaps (probably...hopefully) it is something with which I am already familiar but with another label? Hmmm...

(Darth Vader chiming in..."you are a Fraud...an IMPOSTER - HA HA HA HA...!)