Colour Temp of Enlarger globe

[samcomet]

G'day all,

Just looking for a bit of worldly advice - being one with time on my hands I decided to put my Minolta Color Meter II on the baseboard and discovered that to bring the colour temp (light balance - blue/red ratio) of my enlarger globe to 3200 K (from about 2700 k) and to bring the CC (color correction - green/magenta ratio) scale to a 0 level from -9, I need to add a ⅜ CTB blue gel plus a ⅜ Plus Green 30CC) gel to my light source. These levels are what I used to use when working with colour neg cine film on film sets. Now retired, I only print B & W but I was wondering if people thought that I am being overly pedantic and should probably just get on with printing as per usual? I ask this with reference to Ilford MG filters and the effect that this might have on my contrast values at the top end of the contrast filters scale.

For what it is worth I have read several previous threads on this topic but none addressed the CC levels, only the LB levels.

Thanks for any advice (including the obvious - "just get on with it")
cheers,
Sam

 

[AgX]

The official incandestant non-halogen enlarger lamp is overrated, thus runs only for about 100h, with a colour temperature of about 2800K, with some type even 3000K at 6h. With typically heightened mains voltage here in the the EU these lamps became overrated a second time thus heightening colour temperature a second time.
Over time its colour temperature decreases.

Thus one should be careful not to compare apples to oranges.

With halogen lamps similar considerations apply.

 

[tedr1]

A year or two back I asked Ilford about sensitivity of their variable contrast papers to small changes in incandescent color temp due to mains voltage changes and received this reply

"The Multigrade filter set was designed to work around 2856K tungsten illuminant but I am sure a reasonable change will only have a small effect on the contrast range. A large increase in col temp would shift all contrasts in the "harder" direction. You could compensate by using a 1/2 filter grade lower if necessary."

 

[samcomet]

Thanks for the thoughts from both of you. Will ponder no more.
cheers,
Sam

 

[Sirius Glass]

The OP is not being overly pedantic. It is better to correct the source to the proper color balance. That way any color correction made for any negative on that enlarge should either work or be close for another enlarger.

 

[AgX]

Exactly. My reply was not intented to discourage looking into the matter of lamp colour-temperature, but just to consider variables.

 

[mshchem]

A year or two back I asked Ilford about sensitivity of their variable contrast papers to small changes in incandescent color temp due to mains voltage changes and received this reply

"The Multigrade filter set was designed to work around 2856K tungsten illuminant but I am sure a reasonable change will only have a small effect on the contrast range. A large increase in col temp would shift all contrasts in the "harder" direction. You could compensate by using a 1/2 filter grade lower if necessary."

2856+/- ?? I remember the quest for a voltage stabilizer for color printing back in the 70's. We didn't have voltage fluctuations, but that didn't keep me from worrying about it. Very reasonable question. When weird things start to happen you will have a good record of where you started.

 

[mshchem]

Thanks for the thoughts from both of you. Will ponder no more.
cheers,
Sam

I like the way you think! FYI Ilford makes special paper for all the commercial labs. It's panchromatic, designed to work with RGB lasers and LED printers. None of the commercial machines use ordinary multigrade papers. Makes me wonder what is possible using color negative film and panchromatic paper? Not enough to spend 500 bucks on a couple rolls of paper, but still? If you had one of these fancy LED printers, shot color (film or digital) and exposed each channel separately, you could do practically anything onto black and white fiber base paper. Ansel Adams would be thrilled .

 

[samcomet]

Folks,
I take Sirius Glass and mshchem point about "knowing" where one is from the start, for future reference. I guess that the OCD in me plus having a bit of spare time waiting for prints to flatten got me on this voyage. I do luckily have a bunch of oversized swatch books from Lee Filters left over from my work place that I can insert into my lamp house and do some tests. It'll be interesting to see what the light loss is (it should be negligible) as well as making the comparison between say 2 filter 5 prints and 2 filter 00 prints side by side, with and without my temp corrections. Thinking about AgX and mshchem said, I'm sure that voltage fluctuations here in Sydney may be more of an issue. Anyway I'm back in the dark in another day or two and if there is a discernible difference I'll post the results.

Thanks again all of you,
cheers!
Sam

 

[samcomet]

Folks,
For what this is worth I have made a couple of identical prints, both with and without the colour correction required to bring my enlarger globe to absolute 3200 k with near zero green/magenta tone. I had made two sets of prints, each at both ends of the Ilford contrast filter range. Apart from an aprox 1 stop of light loss from my filter package, I could not discern any real difference in contrast between the corrected and uncorrected prints.
Thanks to you all for opinions on my original post. I guess that I had way too much time on my hands and should've just gotten on with it!
cheers!
Sam

 

[David Brown]

...
"The Multigrade filter set was designed to work around 2856K tungsten illuminant but I am sure a reasonable change will only have a small effect on the contrast range. A large increase in col temp would shift all contrasts in the "harder" direction. You could compensate by using a 1/2 filter grade lower if necessary."

I had a related situation recently. I teach occasional darkroom classes in a facility that I have no real control over. The enlargers are all Beseler 23C and MX4x5. There is a crate of the proper OEM bulbs for the two 4x5, but six of the eight 23C’s had been fitted with an LED “75W equivalent” bulb, rated at 3000K. Since the workshop I held a few days ago was specifically about contrast control, I was concerned about the effect with the Ilford filters.

Bottom line, I did tests. There were some differences, but they were subtle. There was nothing that prevented getting decent prints, and certainly nothing that hampered teaching about using filters for contrast.

I suspect that the Ilford comment is applicable. There are so many variables (and I recognize the OP’s interest in addressing one of those variables.) Sometimes one just has to go with what they have to use. In my own darkroom, I generally print with a color head. (I also have a condenser) According to Ilford, 5 magenta is equal to a grade 2.5, and 25 magenta is grade 3. But some of my prints need 10 magenta! Know what I mean?

 

[Jim Jones]

For many years I used a voltage stabilizer because of frequent power source variations, and a Variac to cut the voltage several volts to extend incandescent bulb life in B&W printing. If this caused any shift in contrast when using variable contrast filters, the change was masked by my sometimes casual printing technique and corrected by reprinting.

 

[darkroommike]

I like the way you think! FYI Ilford makes special paper for all the commercial labs. It's panchromatic, designed to work with RGB lasers and LED printers. None of the commercial machines use ordinary multigrade papers. Makes me wonder what is possible using color negative film and panchromatic paper? Not enough to spend 500 bucks on a couple rolls of paper, but still? If you had one of these fancy LED printers, shot color (film or digital) and exposed each channel separately, you could do practically anything onto black and white fiber base paper. Ansel Adams would be thrilled .

I used tons (well maybe a hundred pounds) of the Kodak Panalure paper back in the day. The best of the bunch was the last iteration, available in three contrast grades. Mini-labs also had black and white RA-4 papers available for a while; Konica and perhaps Mitsubishi. I am intrigued by the new Ilford stuff, why hasn't someone bought a roll and cut it and packaged it like the repackagers do with color papers?

 

[mshchem]

I used tons (well maybe a hundred pounds) of the Kodak Panalure paper back in the day. The best of the bunch was the last iteration, available in three contrast grades. Mini-labs also had black and white RA-4 papers available for a while; Konica and perhaps Mitsubishi. I am intrigued by the new Ilford stuff, why hasn't someone bought a roll and cut it and packaged it like the repackagers do with color papers?

I tried to find a roll of MGIV , minimum order amounted to over a mile of 10 inch wide paper. This is due to there's no demand for rolls of VC regular paper. The panchromatic rolls are stocked and available in less than case quantities. Look for it on Ilford's site, it's available in rc and fiber ( Gallery something ) .

Hey Ilford, make paper available during annual sheet film sales. I will take a box of 12 x 60 Art 300.

 

[DREW WILEY]

Commercial labs routinely using panchromatic paper? Yeah, sure, if pigs can fly. Mini-labs? well, who counts on them for quality results? But frankly, I don't see what the fuss is about. Today's VC papers are geared to tungsten illumination, not daylight. But getting automated enlarger to enlarger consistency requires fully adjustable colorheads on each unit, plus output consistency, plus feedback monitoring using a device way more sophisticated than a basic color meter. I own that kind of equipment (plus a Minolta color meter), but never bother with such antics when using b&w papers. Simple test strips are plenty quick and adequate.

 

[darkroommike]

Commercial labs routinely using panchromatic paper? Yeah, sure, if pigs can fly. Mini-labs? well, who counts on them for quality results? But frankly, I don't see what the fuss is about. Today's VC papers are geared to tungsten illumination, not daylight. But getting automated enlarger to enlarger consistency requires fully adjustable colorheads on each unit, plus output consistency, plus feedback monitoring using a device way more sophisticated than a basic color meter. I own that kind of equipment (plus a Minolta color meter), but never bother with such antics when using b&w papers. Simple test strips are plenty quick and adequate.

Apparently the whole industry rode flying pigs then.

• Back in the day, from about 1970, when professional photographers shooting portraits, what we called, in the industry, main street photographers, migrated from shooting seniors on split 5x7 and hand colored wall enlargements to using CPS and VPS films and making color enlargements, year book publishers and newspapers still screamed for black and white prints for publication.
• Since the graphic art houses refused to alter their workflow and use panchromatic graphic art films, etc. the industry needed another solution. Panchromatic papers made that happen. The original Panalure and Panalure Portrait were FB, The stuff I used was RC. I made 500-600 4 unit sets of wallets for the paper, yearbook, composites that were rephotographed, etc. every year working as the darkroom guy for one studio. Multiply that by the number of main street photographers in just the US alone, THAT is an industry.
• For the main street photographers that didn't have an inhouse darkroom, most color labs that catered to the color negative market also had machines that could do Panalure prints. That was an industry.
• When C-41 black and white materials were introduced first from Ilford and Agfa, Kodak and others to follow. It was now possible to get good black and white negatives in an hour, mostly but not entirely from mini-labs, but also a lot of in house photo industrial photography like police science labs. This meant these small potato industrial labs no longer had to support both a C-41 line and a black and white film processing line. The only problem was, prints from these black and white C-41 negatives had terrible color balance when printed on Ektacolor and Fujicolor RA-4 color papers, hence the introduction of RA-4 black and white panchromatic papers. The birth of another industry.

I also find your characterization of one hour labs as crap to be insulting. I managed a one hour lab several years. A one hour lab is not a custom lab and you are not going to get the type of output you will get in a custom lab, but a 29 cents print is never going to look like a $5.00 custom print of the same size. What you won't get with test strips and multiple test prints is a whole roll of prints in less than and hour and a turnover in excess of 200 rolls per eleven hour day. In between rolls of film and print orders we ran multiple test strips every day and our quality control was pretty damn tight. We also had access to Kodak's Tech Net, just like the big boys.

 

[AgX]

• When C-41 black and white materials were introduced first from Ilford and Agfa, Kodak and others to follow.

not quite..

Both Agfa and Ilford introduced a chromogenic b&w film at Photokina 1980.

 

[DREW WILEY]

An industry or professional purgatory? I sure don't envy yearbook photographers, or the misery of those who had to retouch the zits. Reminds me of the Fuller Brush man who had to travel from one farm to another week after week hoping to earn enough to at least pay for his gas. If someone out there did run a competent one-hour lab, I commend them. But that would be like finding an albino giraffe.

 

[darkroommike]

not quite..

Both Agfa and Ilford introduced a chromogenic b&w film at Photokina 1980.

If I had said first from Ilford, then from Agfa your correction would make sense, I said first from Ilford and Agfa I could have just as easily said first from Agfa and Ilford then from Kodak and others.

 

[AgX]

I read your sentence several times before replying and to me as non-native speaker your wording only makes sence the way I interpreted it, unless you wrote "with Kodak and others to follow".

 

[Sirius Glass]

I read your sentence several times before replying and to me as non-native speaker your wording only makes sence the way I interpreted it, unless you wrote "with Kodak and others to follow".

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