Printing TMAX 100 W/UV bulb?

[tgtaylor]

The 250 watt Halogen, 82 volt GE EVW bulb I had in the Beseler 45S head made its final blink and I replaced it with a UV producing Osram Halogen Photo Optic lamp with the same specification as the GE (same price too - $25). I've read that TMax-100 has a UV blocking filter. The question is whether or not blocking the UV produced by the bub affect printing the negative? I uually print with muti-graded paper but wanted to try printing on graded paper as well.

Thomas

[Drew Wiley]

Colorheads have built-in​ UV blocking filters. Just depends how much still gets through, and even into the film itself. Why not use TMY400 instead? But switching out your EVW bulb to something high-UV might prematurely damage your whole enlarger. It's bad for filters, gaskets, bellows, diffusers etc. Enlargers for UV need special materials. Even most enlarging lenses block some UV. You need the right type lens too. But don't forget the eye safety issues involved !!!

[Duolab123]

The 250 watt Halogen, 82 volt GE EVW bulb I had in the Beseler 45S head made its final blink and I replaced it with a UV producing Osram Halogen Photo Optic lamp with the same specification as the GE (same price too - $25). I've read that TMax-100 has a UV blocking filter. The question is whether or not blocking the UV produced by the bub affect printing the negative? I uually print with muti-graded paper but wanted to try printing on graded paper as well.

Thomas

You can find EVW lamps for 6 to 8 bucks online no problem. If you want a GE there's NOS, Osram makes good bulbs. If you really have a bulb that's pumping out a lot of UV, which I doubt, I would get it out.

[Pere Casals]

I uually print with muti-graded paper but wanted to try printing on graded paper as well.

In theory UV presence produces a change in the contrast grade as it works like blue, many papers are highly UV sensitive. As TMX base blocks UV you should notice less that effect.

Also UV reaching paper has an effect on sharpness, the enlarger lens may have UV transmission while it may not be corrected for UV, so the if paper is highly UV sensitive we'll see some soft focus effect, this is well described in Post Exposure book, Ctein. http://ctein.com/PostExposure2ndIllustrated.pdf , page 149




(http://photographyoftheinvisibleworld.blogspot.com/2011/01/)

193074


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PD: An interesting question is if Ilford contrast filters are blocking UV...

[Drew Wiley]

Cheap bulbs usually don't last long enough to justify the seeming discount. Avoid Chinese mfg. GE no longer makes bulbs, but there are probably still a lot around. Be certain they're US made, since GE also imported junk versions. EU or Japanese Ushio bulbs are also good.

[Jac@stafford.net]

Are you sure the UV filtration is not removed in the fixer?

[koraks]

Are you sure the UV filtration is not removed in the fixer?
100% positive. Anyone who has tried making alt process prints from tmx negatives can assert that the UV filtration is inherent to the film itself.

[Pere Casals]

Yes... in carbon and Pt/Pd UV printing exposure has to be 8 times longer because TMX blocks UV by 3 stops aprox. It has been said that the UV absorbing dye is in the film base plastic. Many plastics are manufactured with an UV absorber mixed in, in that way plastics are not damaged by direct sun rays over time. If the UV absorber is inside the plastic then obviously it would be extremly difficult to remove it.

While it is possible to use TMX negatives for alt UV printing it happens that exposure has to be very long, 8 times longer than usual, IIRC it was Sandy that measured this with an UV densitometer.

[Drew Wiley]

The question is why? TMX was originally engineered to replace a suite of older films, including some marketed mainly for technical applications, astronomical usages included. It was also recommended as a partial replacement for Tech Pan, which had extended red sensitivity, so UV cutoff would have been appropriate in similar applications. I have reason to believe that even now the bulk of TMX sheet film does not go to regular photographers like us, but to technical and industrial usage. So I have some hunches, but no definitive answer. Adding a UV blocker to protect the base from sunlight degradation wouldn't make sense. Who's going to stand out in the sun staring at the same negative for ten years straight? That PET base is pretty robust by itself; so this must have something to do with precise spectral sensitivity relative to intended ranges of use. My spectrograms of TMX100 vs TMY400 are out in the lab, so I can't check them at the moment, nor is the full answer likely to be found on ordinary photo forums. You'd have to check for scientific and forensic applications.

[Pere Casals]

The question is why?

If Ctein's theory is right, (Post Exposure, page 145, http://ctein.com/PostExposure2ndIllustrated.pdf) then in certain conditions UV presence may led to a loss of sharpness in the print, if the enlarger lens is not well corrected for UV.

Perhaps Kodak wanted to address this potential problem... I cannot see another motivation (still it can be there...), because if the blocking is in the base then UV reaches the emulsion anyway during the taking, so mostly UV blocking would be intended for the printing. Of course I'm speculating because I don't know any source explaining why kodak does that.

[Drew Wiley]

I doubt he actually tested for it, but sounds reasonable. What he might have done is look at the effect under his microscope using UV light. Not good for the eyes. I haven't visited him for awhile, and can't remember if we ever discussed that. He's busy working on SciFi novels now.

[interneg]

I recall that the UV claim was tested by others who could not repeat the experiment - I think Ilford couldn't repeat it, nor could Barry Thornton. There's a fair few problems with Post-Exposure once he wanders away from masking & dye-transfer, but all written up in such an authoritative tone that it seems unchallengeable.

As for the TMX layer, I'd take a reasonable guess - unless someone has the microtomed cross section of TMX - that it's quite possibly just an additional supercoat layer added for extra physical protection for handling in Readyload use - especially given the issues Kodak initially had had with TMX & normal 120 base. UV filters etc are in C-41 & E-6 films' coating structures.

[Drew Wiley]

Well, I have some inside knowledge of what he actually tested and what he merely hypothesized; and some of the latter actually went into Kodak tech literature; but those were kinds of things nobody was likely to do commercially with TMax anyway. But Kodak wanted to market it up front for a very wide range of usages, even if some now seem esoteric. Unlike original FP4, TMax films were fairly robust to begin with. Readyload came later, and they sure bellyflopped with the double-sided version of it first. I only shot it in sheet film back then, so can't comment on its fragility or lack thereof of the original roll film emulsion, though I shoot a lot of current TMax 120 these days.

[Pere Casals]

unless someone has the microtomed cross section of TMX

It's way easier. Just place a roll film end in a hot enough water bath and the gelatin will dissolve completely, leaving the film base perfectly clean, so its UV opacity of can be measured. We can compare before/after the hot water bath.

[interneg]

and what he merely hypothesized; and some of the latter actually went into Kodak tech literature

Was that the piece that suggested methods for separating colour negs for making matrices on the regular (as opposed to pan-matrix) matrix film? I've been considering the idea of reversal processing to get to the same end - if I ever get round to having a go at making up some of the Browning Matrix emulsion, but currently I'm rather more interested in making 4-colour gravures by analogue means - which has its own set of challenging registration issues...




It's way easier. Just place a roll film end in a hot enough water bath and the gelatin will dissolve completely, leaving the film base perfectly clean, so its UV opacity of can be measured. We can compare before/after the hot water bath.

I think you might have a difficult time of that with a BVSME hardened set of emulsions - and why would Kodak make a specific polyester base solely for one product, especially when all their colour products have a process-surviving UV filter layer which could be easily implemented on other products?

[Pere Casals]

I think you might have a difficult time of that with a BVSME hardened set of emulsions - and why would Kodak make a specific polyester base solely for one product, especially when all their colour products have a process-surviving UV filter layer which could be easily implemented on other products?

I've just checked it with just a 4x5 TMX sheet, emulsion does not dissolve (BVSME) as you predicted, but after a few seconds in very hot water emulsion is easily removed even with fingers.

193161

When I can I'll check if the base alone blocks UV, as it has been said.

[jnantz]

The 250 watt Halogen, 82 volt GE EVW bulb I had in the Beseler 45S head made its final blink and I replaced it with a UV producing Osram Halogen Photo Optic lamp with the same specification as the GE (same price too - $25). I've read that TMax-100 has a UV blocking filter. The question is whether or not blocking the UV produced by the bub affect printing the negative? I uually print with muti-graded paper but wanted to try printing on graded paper as well.

Thomas

Hi Thomas
My wishy-washy answer is .. maybe, it might increase your exposure time, but probably not by much.
My uneducated guess is on account of many years ago I was in France and gathered the ingredients to make some Caffenol C with my Father in Law in his laundry room. I purchased El Gringo coffee from the local grocery store ( it was the cheepest instant they had ) and the Sodium Carbonate+Vitamin C from the Corner Pharmacy. The Developer was mixed and the sheets of TMX+TMY were shuffled in it while the faint moonlight came in through the basement window. After the film was dried and transported with me back to the states I realized it was too dense to print in my enlarger, and too dense to print on Azo, and took too long in the Sun, so I used RC paper and used the same 300W flood light that I always used to print Azo. The images from the TMY took on average 6 seconds, the TMX took on average 20 or 30 seconds. I attributed the drastic increase of time to the anti UV layer, and when I asked people here and othe places who knew much more than me, they also suggested that might be the reason for the additional time. I am guessing your negatives aren't too dense to see through, so the extra time it takes to expose won't be too much.

Have fun with the new bulb !
John

[Sasquatchian]

How much UV do you think any halogen bulb actually produces, and does it produce enough to make a difference. Every halogen bulb I've measured with the Sekonic 700C has a fairly straight line spectral curve with almost nothing at the blue end. Even though that meter only measures visible spectrum, I have a hard time believing there's a spike in UV after a steady decline in that direction. I also have a specialized meter measuring UV-A/B and every halogen I've subjected that to doesn't move the needle.

[Pere Casals]

How much UV do you think any halogen bulb actually produces

Many halogen bulbs do not throw UV beacuse they are made with UV absorbing glass https://www.ledvance.com/products/product-knowledge/halogen-lamps/professional-knowledge/uv-filter-technology/index.jsp


Some high power lamps allow to pass UV to not reheat the glass.

[Drew Wiley]

Pere - that UV tweak only absorbs some of the UV, by no means all of it. All of the halogens used in enlargers put out a lot of UV. The effects are dramatic on everything inside a colorhead over time. Just to preserve the dichroic filter set longer, it's necessary to have a supplementary UV filter at the doorway, so to speak. Put a color print of any kind under these as low-voltage display lighting and see how long they last - might fade faster than in sunlight. I have no idea how Sasqauatchian comes up with his idea. No lighting pro in the world would claim that.

[Pere Casals]

Well, 400nm violet is in practice as energetic as 401nm UV. Limit is a bit artificial.

[Drew Wiley]

Interneg - I just noticed your question. Yes, it concerned a hypothetical method for making interpostives from color negs, t it then to b&w internegs, for sake of exposing onto regular matrix film rather than Pan matrix. He never actually tried it. I did. It's quite tricky. I should hit the nail on the head a second try, but have no interest in that wild experiment for awhile. I did get a wonderful print from the original color neg onto Fuji Supergloss medium. And I took the green separation neg to make a very nice b&w print onto MGWT due to the wonderful expansion and greater contrast of the separation neg. So it was worth it and fun to try at least once. Pan matrix film could be made again if someone was really determined. I bought out most of the last of Efke matrix film, which was based on Jim B.'s formula, but most of it remains frozen.

[Drew Wiley]

I should add that if I had done the double neg method using TMX100 for both the interpos and interneg, it would have been easy. But since I was just having fun and trying to save money, I only used pricey 8x10 TMX for the first step, the actual color separations.

[interneg]

Pan matrix film could be made again if someone was really determined.

The biggest headache seems to be what the black absorber dye actually was - or if it was a dispersion of carbon black in the gelatin. Some of the patents that seem to relate to the revival of Technicolor in the 90's suggest the latter, but it's never been entirely clear what was used in Pan Matrix.

And all because I want to make colour darkroom prints with a 5K type of finish...

[Drew Wiley]

Jim Browning could tell you; or at least he has made it known that his own formula of matrix film could easily be tweaked to pan sensitivity. You even have to be extra careful with the intensity of red safelight conditions using it. The newest matrix film being used in Germany is designed for blue laser exposure, so might be quite different; but it's not available for public sale anyway. At my age, I have no interest in building my own slot coater. I'm having a hard enough time just getting back to regular dye transfer experiments, though what I was really learning to do was a modernized tweak of the previous wash-off relief technique, which is more practical for me. In the meantime, I'm really buried under a big backlog of RA4 printing, which I've got good enough at to truly rival or excel DT in certain respects, lots of new black and white printing work, and a huge backlog of drymounting.

[interneg]

Drew - I think you might be referring to a bit in Ron Mowrey's emulsion making book where he suggests a possible route & dyes to making pan-matrix subsequent to an appendix containing the Jim Browning recipe - and explains the need for a black dye (but doesn't specify anything that might be a suitable candidate) in place of the yellow dye used in the blue sensitive matrix film, as well as most of the other headaches involved in making pan-matrix work well.

What are you using for your bleach in the wash-off process? I'd like to avoid the dichromate bleaches like R-10a if possible.

[Drew Wiley]

My wash-off relief method does require a bit of ammonium dichromate - nasty stuff, but I do this in drums, so not much risk. I haven't researched an alternative yet. Please note that I'm a beginner at this. I do know how to make very precise color separations and masks, but just haven't had time to get too far into actual printing other than the basics, to confirm that my method does work well. I've developed matrix film both the official quickie dye transfer way and, to my thinking, the preferable slower wash-off relief method, which gives me better process control because it's not so rushed, and is way more economical. I use HC-110, but it's been commercially done with DK-50. The Efke matrix film tends to have minor blemishes or specks from bits of gelatin floating around that got re-deposited on the film during mfg; but it's not a huge problem because DT is not an extremely sharp process under the best of circumstances and doesn't warrant especially close scrutiny. The strong point is the potential for hue control and the transparency of the dyes. I just want to do it for fun and the challenge; there are far easier ways to make excellent color prints in the darkroom. But I haven't looked at Ron's book. I e-chat with him frequently. It's amazing that he's still so active at his age.