The concept of additive/subtractive does not really apply to darkroom printing. I suppose one could sort of use the term additive if a source directly emits only the target wavelength(s) to which the print medium is sensitive, but it still doesn’t really mean anything. The paper doesn’t care what colour you see.
It can make wading in cold bunker fuel seem an attractive option.Originally Posted by Mark J
The 138s condenser head is very simple - and can take a lot of heat (it's designed to take up to 1000w tungsten - if you use the blower at 300w+) - and things up to and including xenon lamps. At the end of the day, it's a 1940s solution to evenly illuminating a fairly big set of condensers.
Additive /subtractive does not apply to darkroom printing? Tell that to hundreds of prints of mine, as well as to those who were trying to make all of Durst's commercial colorheads additive toward the end of that division, or to former NSA engineers who demanded custom 8X10 additive colorheads at great expense. But at least you "suppose" the term additive applies if the source emits only the target wavelength? You've sure got an engineering problem there. What one wants is a blackbody source with only a specific narrow slice of the spectrum getting through each of the respective RGB filters, so in effect you are dealing with three pure sources.
That's not the case with subtractive CMY colorheads, or drawer filter sets, where you've removing an amount of the complementary primary, but still a certain amount of unfiltered "white" light is getting through and affecting the exposure to some extent. How much does this distinction matter? Sometimes quite a bit in the past. Color prints made additively had much cleaner purer hues. But newer chromogenic papers have narrower spectral response peaks, certain color negs too. And later generation colorneads began to have less white light spillover. So yes, even today I could see the difference between a print made with one of my additive enlargers, and the one I did with an especially nice CMY colorhead. But it's not enough of a distinction anymore to make a fuss over it. With critical tasks like making color separation negatives from chrome, it is a crucial difference. VC printing? - Na. I can achieve almost identical results either way, or split printing too.
I'm just going to re-cap on some of the format masking that was mentioned earlier in the thread.
Can I conclude that the geared masking strips under the neg carrier are not enough to mask light around the neg properly ?
I can't remember 100% but I'm thinking the seller said something about that working for eg. 6x9 ,but not for 35mm....
For glass 6x9 enlargement and 35mm , maybe the Ladane is the best option if I can find one ?
This has 70mm glass top & bottom as standard ?
It is the same size as the 5x7" glass plates in the Nega 138, so you take the standard glass out, to use it ?
Presumably for 4x5" you can make a card mask that can sit over the anti-newton upper glass ?
I noted Tin Can's comment about a smaller enlarger sitting on the baseboard , for doing 35mm. That's a cute idea, actually !
The adjustable masking masking blades below the carrier will block off stray light at the baseboard easel, but are spaced too far from the neg carrier itself to do so crisply. There was a later neg carrier with its own set of masking blades directly beneath the lower carrier glass; but these rarely turn up, are quite expensive, and need their own special adapter. Why not just rely on the adjustable masking blades on pro easels themselves? The built-in blades below the carrier sometimes need to be re-adjusted to their correct symmetry. It's not hard to do once they're exposed; but you have to disassemble certain things to get in there.
I use Nega 138 carriers most of the time, along with simple format masks which I've cut from voided polyester Cibachrome film base using a razor knife and straightedge. I also use 5X7 Durst Anti-Newton glass both above AND below the film.
For 35mm negs I have a recessed lensboard is using a short lens like 50mm. But I normally print 35mm film with something longer for sake of more spacing distance, like 75mm or 105mm. My own "small" enlarger is a floor-mounted 138. All the others are 8x10 units.
Ok , good info thanks.
I have a Beard 16 x 20 easel which I use for everything. On the Meopta I currently use, you also have to get the adjustable masking strips fairly close to the neg edges to avoid uniformity issues near the picture margins. Hopefully the Durst ones serve that purpose, from what you say.
I can cut masks if needed. I don't have any Cibachrome ( you've got me on that ) but I can find something suitable.
I did get a nice sunken adaptor for ~50mm lenses, I will see how that goes.
I'll post a pic of the enlarger assembled in the front room, shortly.
No, I'll post this information first, this going back to the question of what 'Blue' means in the context of Ilford Multigrade.
I have now got two very useful graphs.
One is courtesy of Ilford technical staff. This is the sensitivity vs. wavelength of the blue-sensitive emulsion :
Ilford couldn't get the green-sensitive curve directly, but advised that I can construct it by graphically removing this blue response from the overall ( safelight info ) curve contained in their MG Paper datasheets. I will try to do this when i get time.
These two graphs show transmission measurements of the G5 and G4.5 gel filters. The blue curve is the G5 filter.
Thanks Mark, the blue sensitivity extends much more into the violet and near UV than I was expecting when I chose royal blue LEDs (450nm) for my black and white head experiment. Definitely evidence we should probably be using LEDs closer to 400nm than 450nm if maximum contrast is the goal. I may try to switch out the LEDs in my VC head to test this out.
You could have just looked at the spectral sensitivity of Galerie https://www.ilfordphoto.com/amfile/f...1/product/722/
No, I'll post this information first, this going back to the question of what 'Blue' means in the context of Ilford Multigrade.
I have now got two very useful graphs.
One is courtesy of Ilford technical staff. This is the sensitivity vs. wavelength of the blue-sensitive emulsion :
Ilford couldn't get the green-sensitive curve directly, but advised that I can construct it by graphically removing this blue response from the overall ( safelight info ) curve contained in their MG Paper datasheets. I will try to do this when i get time.
These two graphs show transmission measurements of the G5 and G4.5 gel filters. The blue curve is the G5 filter.
Ha ! Well, that's quite interesting. When did you notice this ?
I see no reason why these should be the same - after all, the spectral response of RC Multigrade is not the same as FB Multigrade Classic.
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