Please help. Insufficient color filtration.

[Konalog]

The last generation of Durst enlargers included a supplemental RED filter for such cases. In your case, a similar RED filter somewhere in the light path would be of benefit.View attachment 321886

Please see my most recent comment in this thread.

 

[4season]

The only other thing I can think of is to try a lamp specifically designed for use in an LPL enlarger, if there isn't already one installed. I can't recall whether there was something out of the ordinary about the bulb in mine.

Edit: I lied, I thought of another possibility: If voltage is running higher than expected, I'd expect the lamp's color temperature to rise, and hence, it's spectrum to shift more towards blue. If you have the means to do so, try measuring to ensure that voltage with lamp installed really is 12 volts or close to it.

By the way, what are your typical paper exposure times?

 

[Konalog]

The only other thing I can think of is to try a lamp specifically designed for use in an LPL enlarger, if there isn't already one installed. I can't recall whether there was something out of the ordinary about the bulb in mine.

Edit: I lied, I thought of another possibility: If voltage is running higher than expected, I'd expect the lamp's color temperature to rise, and hence, it's spectrum to shift more towards blue. If you have the means to do so, try measuring to ensure that voltage with lamp installed really is 12 volts or close to it.

Much appreciated, thanks.
The same idea did cross my mind for at least a few seconds - that the luminol output, or frequency may be off, but I don't even know where to get a multimeter to measure the output from the enlarger's adaptor. Well I do have a replacement bulb. Might as well try switching it out . Not trying tonight, but if it works I'll let you know.

 

[4season]

Fujifilm datasheet for CA paper is very interesting, showing relative sensitivities of the blue-, green- and red-sensitive layers at specific wavelengths of light.

https://asset.fujifilm.com/www/us/f...icolor_Crystal_Archive_Type-CA-Data-Specs.pdf

And your prints suggest that your light source is too freaking blue, but whether due to incorrect bulb or too-high voltage..?

 

[DREW WILEY]

Seems you want to blame the enlarger colorhead regardless; but a different enlarger might not help at all if you don't pin down the actual problem. Do this. WITHOUT any negative in the carrier, put a white card on your baseboard, then look what color you see with maximum Yellow /M zero/ C zero; then repeat Y zero/ maximum Magenta / C zero; then finally Y zero/ M zero/ maximum Cyan. Then tell us the result.
That should at least resolve if there's any issue with the filters or not. First things first.

Don't blame Kodak either. Their quality control of color neg films is superb. Fuji has its own superb quality control and consistency of papers, though papers do sometimes get stored improperly or sold out of date, typically symptomized by grayish-yellow borders.

If one is trying to make sense of paper spectral sensitivity curves on the Tech sheet, you need to remember that those factor in the blue overcoat of the paper in relation to the orange mask of the film; and as a negative system, it's inverse.

 

[MattKing]

Print #3 looks like what you might get if the cyan filter itself is stuck in the light path. When I look at the first photos you posted of the light within the light source, that light is also surprisingly cyan.
Perhaps the cyan filter itself has come loose from its control.

 

[Konalog]

Print #3 looks like what you might get if the cyan filter itself is stuck in the light path. When I look at the first photos you posted of the light within the light source, that light is also surprisingly cyan.
Perhaps the cyan filter itself has come loose from its control.

You're correct about seeing cyan light, because I had that one turned all the way up, and the others lower down. But no, I've watched as all 3 filters move through their full range individually when turning their respective knobs.

 

[koraks]

Edit: I lied, I thought of another possibility: If voltage is running higher than expected, I'd expect the lamp's color temperature to rise, and hence, it's spectrum to shift more towards blue.

But not by the extent we're seeing here. The difference would be far more subtle. The same with frequency variations (which will have no effect at all on a tungsten bulb).

I don't even know where to get a multimeter to measure the output from the enlarger's adaptor.

Not sure about your country, but around here, any DIY store sells them. But I wouldn't bother - this is not the cause of your problem.

It really starts to look like there's something very wrong with your filters, unless there's an odd issue with your RA4 chemistry. You mention it's Arista - can you link me to the exact product you're using? Both developer & blix. Are you using a stop bath as well? What temperature are you running the process at, and what development time do you use?
You might do one experiment: set up some trays for development & blix and run a couple of test strips through them at room temperature using a development time of ca. 90 seconds. See if this makes a difference. If the results improve and you get more normal filtering settings, you have a (severe) process control issue. If the results don't improve, there's still the possibility of chemistry contamination etc. although I'd suspect more problems with fogging in this case.

 

[brbo]

1) M = 170 (max), Y = 200 (max), C = 0. PLUS: 10M gel and 1/2 of a 10 Y gel (see pic) taped to the mixing box entry aparture.

2) Exactly as above, but with the M, and Y filter settings decreased to M = 160, and Y = 190. Gels unchanged. Not kidding.

So, the only difference between 1 and 2 is -10M and -10Y and you get a massive shift from reddish to cyan on paper? And then further decreasing the filtration (albeit much more) shifts it back to full red?!

Have you established that all differences you get on paper are the result of changing the filtration on the enlarger? Like, you can do 5 prints at M170 Y200 and all will be reddish and then decrease both by 10 and next 5 prints will be cyan?

I have LPL7700 (I think that's basically the same enlarger as you have), my typical filtration with this enlarger is in the range 70-100. That's higher than you typically see in other enlargers, but I have an IR filter installed (as per manufacturer's recommendation for colour printing).

 

[Konalog]

So, the only difference between 1 and 2 is -10M and -10Y and you get a massive shift from reddish to cyan on paper? And then further decreasing the filtration (albeit much more) shifts it back to full red?!

Have you established that all differences you get on paper are the result of changing the filtration on the enlarger? Like, you can do 5 prints at M170 Y200 and all will be reddish and then decrease both by 10 and next 5 prints will be cyan?

I have LPL7700 (I think that's basically the same enlarger as you have), my typical filtration with this enlarger is in the range 70-100. That's higher than you typically see in other enlargers, but I have an IR filter installed (as per manufacturer's recommendation for colour printing).

IR filter huh? Never heard of using one when making a print. Is the difference noticeable?

 

[Sirius Glass]

IR filter huh? Never heard of using one when making a print. Is the difference noticeable?

An infrared filter would filter out the needed visible color of light from the enlarger light source. One out be better off putting a lens cap over the enlarger lens.

 

[brbo]

IR filter huh? Never heard of using one when making a print. Is the difference noticeable?

I only see difference in filtration needed to get a properly balanced print, but I can get exactly the same final print with or without IR (heat absorbing) filter in place.

Pull out the silver holder and see if you have the IR filter in place, too.

 

[DREW WILEY]

Wrong. UV filter. Or a single combined glass coating might be involved. But the absence of that would only mean a tiny bit more overall blue. Modern colorheads remove most of the heat itself using a fan system.
And in this case, we're dealing with a small colorhead anyway. The dichroic coating on the bulbs themselves also helps.

Another point - the extreme filtration involving supplementary colored gels is a recipe for for incurable counterproductive curve crossover.

 

[Konalog]

Possible solution found.
I noticed that a tiny notch at the top margin of the bulb was not fully seated in the bracket (as seen in the attached pic). Not at all obvious even on close visual inspection - only discovered when I attempted to switch out the bulb as a last resort. So I secured the bulb, and did 2 test strips: #1 with Y/M both set to 100, then #2 with Y/M maxed out. No gels, and C=0 for both test strips. Both showed a heavy cyan shift. I'm going to try making some more test strips tonight with more reasonable Y/M settings around 70/60, etc and see what that shows. If this solves the issue, then everything may have stemmed from only a slightly malpositioned bulb, possibly loose enough to allow some movement between prints, resulting in unpredictable results. But we'll see tonight.

 

[brbo]

Wrong. UV filter.

Wrong. IR filter.

 

[Konalog]

I only see difference in filtration needed to get a properly balanced print, but I can get exactly the same final print with or without IR (heat absorbing) filter in place.

Pull out the silver holder and see if you have the IR filter in place, too.

View attachment 322011

Oh yeah, this is the UV glass. I have the same. Tried cleaning, etc.

 

[Konalog]

Wrong. IR filter.

I stand corrected.

 

[MattKing]

For clarity, the IR filter is used to reduce how much heat reaches the film, thus reducing the problems with negative movement during exposure. A properly positioned IR filter should have either no affect on the colour balance of a print, or a minimal but consistent affect.

 

[DREW WILEY]

Hmmm. Doesn't resemble anything in my own colorheads; but those are all commercial grade. I admittedly have no personal experience with Saunders enlargers. Negative flatness is a endless struggle anyway, unless one uses a full glass sandwich carrier.

Cleaning dichroic filters is a very delicate process. They don't fade per se, but will gradually spall off bits of coating over time if overheated, and in that manner lose their efficiency.

 

[brbo]

For clarity, the IR filter is used to reduce how much heat reaches the film, thus reducing the problems with negative movement during exposure. A properly positioned IR filter should have either no affect on the colour balance of a print, or a minimal but consistent affect.

Top - no IR filter, bottom with IR filter. RGB filtration the same on both.

 

[DREW WILEY]

IR means heat per se. Where does any paper spectral chart show the sensitivity curve significantly extending into IR territory? What is posted above is more symptomatic of an excessive amount of UV coming through. But like I already noted, mixing box input filters can potentially contain both relevant coatings on the same piece of glass.

 

[MattKing]

Top - no IR filter, bottom with IR filter. RGB filtration the same on both.

That's much more of an effect than I've seen before. Did you post the offset necessary to make the results match?

 

[brbo]

Unfortunately, I can't find the non-IR filtered print that matched the IR filtered one.

 

[mshchem]

Possible solution found.
I noticed that a tiny notch at the top margin of the bulb was not fully seated in the bracket (as seen in the attached pic). Not at all obvious even on close visual inspection - only discovered when I attempted to switch out the bulb as a last resort. So I secured the bulb, and did 2 test strips: #1 with Y/M both set to 100, then #2 with Y/M maxed out. No gels, and C=0 for both test strips. Both showed a heavy cyan shift. I'm going to try making some more test strips tonight with more reasonable Y/M settings around 70/60, etc and see what that shows. If this solves the issue, then everything may have stemmed from only a slightly malpositioned bulb, possibly loose enough to allow some movement between prints, resulting in unpredictable results. But we'll see tonight.

I've been in your situation, well sort of. The first thing is it looks like you have white paper where shielded from the enlarger, so this isn't likely to be some weird chemical fogging, or fogged paper. If you develop a sheet of paper without any exposure to the enlarger, and it's white, it's not the chemistry or the paper.

I really can't help but think that there's a situation effecting the filtration. That much of a red cast is calling for M & Y, which when you add with the gels you're seeing improvement.

Is there a "white light" function on these colorheads that takes the filters out of the light path for focusing? My Beseler 4x5 Dichro S head has a "paper saver" circuit, that prevents exposure with the white light lever engaged.

If you have that much filter density engaged your exposure times would be really long. There's got to be something wrong with the filtration.

 

[mshchem]

I found the manual, there's a white light lever on the left front of the color head, if the filters are removed from the light path with this lever a white light should illuminate on the front panel of the colorhead. The filtration values are dialed in but this lever raises all the dichroic filters out of the light path. Check this.

James's Camera Collection: Manuals and Documentation

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