RA4: Red Mist

[Roger2000]

Hello,

Slightly similar post elsewhere a week or two ago, but think the problem has changed hence the new post in a new category.

I've got a durst m605, colour head, which has worked fine for a few years, producing good colour and black and white prints.

I recently started colour printing again, on cut sheet Fuji in fresh Kodak chemicals at 35 degrees. However, the prints had a red cast even on max red filtration. I've just cut down some new Kodak endura, and these prints too are red even on max magenta and yellow filtration.

I've changed the bulb but it's just the same.

I've also noticed that contrast is now lacking in black and white prints, suggesting a weaker than usual red filter.

To my mind, either the brand of bulb is wrong, or the magenta filter in the enlarger has burnt out / dulled over the years.

I've attached a picture of the bulb I'm using.

If anyone has any thoughts on what might be the cause, I'd be very grateful for your views, before I chuck my enlarger on the skip.

Thank you!

 

[Svenedin]

I don't do colour printing but you do mention lack of contrast with black and white. My enlarger uses the bulb in your picture. If your enlarger uses dichroic filters then these don't burn out or fade. Worth having a look inside the head to see what is going on. Perhaps the mechanism is not properly moving for the magenta filter or maybe it is very dirty in there. If your exposures are longer than usual as well as lacking contrast then maybe there is an electrical problem. If you decide that your enlarger is beyond repair I'd recommend enlargers made by Kaiser (German). These are available second hand or new, very well made, easy to use and parts are readily available (and still made).

 

[Roger2000]

Thank you. I've had a look and the red filter is definitely moving in the correct fashion when you move the dial and the image on the baseboard visibly darkens when you turn it up. I'm baffled.

 

[Bob Carnie]

You mention Red filter... are you working on an Additive Enlarger??

 

[Roger2000]

No, normal durst m605 dichroic. Magenta filter is the correct name sorry.

 

[Bob Carnie]

No, normal durst m605 dichroic. Magenta filter is the correct name sorry.

Ok - there are many variations of Bulbs, it looks like the right one but I would check this aspect as it may indeed be the wrong one... I doubt the dichroic is the problem but it may be slipping and you can open the head a bit and make
sure the filter is reacting like the Yellow and the Cyan.
If it is sticking you will not get full magenta, but you should be able to see on a white sheet the colour getting more Magenta as you dial it in.


I use OSRAM ELH 300W - 120 V for my Devere Dichroic enlarger...

 

[Roger2000]

Thanks for your thoughts - I've had the head off, poked around, everything seems normal. I've moved the red filter, and yellow, progressively in and out and the dial clearly works. At maximum magenta filtration, the photos come out with a slight red cast, and I'm stumped as to how to solve it.

 

[Bob Carnie]

I would then move away from the enlarger being the problem and consider the paper and chemistry as the issue... over 30 years printing with a dichroic enlarger for colour and I never heard of Maximum magenta being needed unless the original negative was abstract in itself (cross process or solarized)

Sometime a ELC bulb is floating around which may not be suited,, PE or Gerold may have ideas on bulb type , or that of other colour printers still using an enlarger.

 

[Roger2000]

I don't think it's paper. I'm using a fresh roll of Kodak paper and the same thing happened with cut sheet Fuji paper.

The chemistry is fresh Kodak.

I've just changed the bulb but they were both the same brand, so I supppse that could be it.

I am completely stumped otherwise.

 

[Bob Carnie]

Wish I could help you more... Sometimes its the most silly thing... for example a small led light from some device could seem quite insignificant but will cause a red cast... look around the room you are working in total darkness and see is by chance something is emitting light .. does not have to be much as colour paper is very sensitive...
You have had success with the chemistry before , the paper is fresh, unfortunately and based on my history it is something simple which we have a name for here, OE operator error , I never blame the chemistry and paper unless its the absolute last resort.

good luck.. eliminate all the variables one by one rather than a bunch at a time and you will find the culprit.

 

[Roger2000]

Cheers Bob. There is a red led in the darkroom. Only very small but....., I'll cover it up and report back.

 

[Roger2000]

Alas, even with the little led covered, the print's still too red on max magenta. Prints should surely turn green when the magenta is on full. In this case, there's a faint red cast. I'm completely flummoxed.

 

[Bob Carnie]

the red light would probably cause a cyan cast that you would then have to filter out with Magenta , so it kind of makes sense.

 

[Photo Engineer]

Sounds like there is a lot of cyan filtration in the light beam, which would also perhaps explain the low contrast B&W if you are using MG paper.

PE

 

[Roger2000]

Thanks Ron, I can see how that idea would make sense, but the cyan filter is always on 0. The exposure on RA4 takes about 2 seconds at f5.6 so I don't see how there can be any stray cyan light interfering.

 

[MattKing]

he cyan filter is always on 0.

Is the actual filter itself stuck in the light path, even when the dial is set to zero?

 

[Bob Carnie]

Is the actual filter itself stuck in the light path, even when the dial is set to zero?

that can happen, need to look inside.

Also check the mixing box chamber next for oddities.

 

[Roger2000]

Hello all - thanks for your thoughts. I've cleared the light path and then jogged the magenta, yellow and cyan dials up and down, and you can see the light becoming increasingly yellow / magenta / cyan in line with the dial, with the maximum filtration reached when each dial gets up to 170 (130 with cyan). As far as I can see then, the dials and filters are working.

I've tried making a print with a 'normal' colour balance, using notes from previous prints made on the enlarger with supra endura, and the prints come out tomato red. Just to test the system, I then kept the Y filter on 60Y and shot the M up to 170. At that filtration the print comes out still red, but not AS red, as if it needs another 20 units of magenta.

Odd.

 

[WilmarcoImaging]

If fresh chemicals and fresh paper and undamaged/properly exposed and developed negative and accurate paper exposure time/temp and accurate paper developing time/temp then problem likely in the parts not mentioned, i.e. Light source or stray light. What else is there to evaluate?

 

[Bob Carnie]

light source is still in question IE bulb type.... stray light has been addressed... I would consider re mixing chems from scratch and see if problem exists.

 

[Bob Carnie]

also seen it before, some of the enlargers I work with have a light for you to see the filter numbers, will fog paper

 

[Bob Carnie]

the only time I saw prints come out completely red, a technician in the late 70's put rolls of exposed paper( whole day production of a busy wedding lab) in green garbage bags and turned on the lights to look at a processor problem, needless to say that technician lost his job for this.

 

[perkeleellinen]

I would try placing a sheet of paper on your easel but don't expose to light. Leave it there for a minute and then develop.

 

[Roger2000]

Thanks again for your comments gents.

I don't think it can be the illuminated dials as I've used this enlarger for years and only now has this become a problem. If they were causing a colour cast, it would have happened long ago.

Secondly, I take your point (perk) about exposing a blank sheet, but the white bits of the paper (such as borders) come out perfectly white. There isn't any red staining on the paper, just a cast within the image. I'll give it a go though and see what comes out.

Cheers all!

 

[perkeleellinen]

I think white borders would rule out a chemical fault. However, those parts are masked by the easel blades so it would be worth seeing if a blank sheet goes white.