Problem with Ilford MG filters... Simon ??
In the community darkroom that we recently set up for the "overexposed" team (www.overexposed.eu - the site is under construction but some pages are up) we have two condenser head enlargers. Both of them are brand new Kaiser models, one 35mm and one MF.
We bought two sets of Ilford Multigrade over-the-lens filters to match them, which perfectly fit the filter drawer of the enlarger.
After they have been used a couple of times some of the filters are showing a strong decoloration in the middle (a circular shape with blurred edges that seems like the shape of the opening that the light from the lamp comes and hits the filter). The grade 4 filter seems to be particularly hit by the phenomenon, although it might have been the one that was mostly used...
Although I understand that usage and the effect of light and heat can discolour gelatin filters, I feel that this has happend too quickly in this case, since the darkroom has been in use for only a few weeks (and not every day).
Has anyone had a similar experience with a recently purchased set of MG filters from Ilford ? Has Ilford changed something in the manufacturing of MG filters lately (I personally own a set since 1989 or something and it's still in top notch condition) ?
I know that the dyes used are water soluble, but I am sure that in the specific case no water or humidity has come in contact with the filters, this is something that creates much different marks on the gelatin.
Simon, does your company cover this kind of "product malfunction" ? If I come in contact with the Greek importer, the most they can do (if they do) is to replace the product with a box of the same kind, that will be in the same condition in a couple of weeks... is there something to do in order to get a set of filters that will not lose its colour after a few hours under the Kaiser enlarger lamp ?
Interesting. I rarely use filters over grade 3 1/2 but had occasion to last week. I would have expected that the exposure time for the grade 4 filter would have been (approximately) twice the exposure for the grade 3 1/2 filter, but in fact exposing through my grade 4 filter gave a very dark (much overexposed) and very low contrast print (about grade 1.) My Ilford filters are probably ten years old so I simply thought that it was time to replace them. Examining the grade 4 filter in white light, it appears to be a light yellow in color and is mottled -- the color isn't solid across the filter's surface.
So, I need to get new filters. It doesn't surprise me: I never expected them to last forever. Now the real question: throw my Kodak filters away or wait 50 years and sell them on eBay as collectibles?
I suspect the filters are getting too hot for too long:
Originally Posted by George Papantoniou
Maybe lamp has been left on "focus" for a long time (overnight, over the weekend??)
Maybe lamp house has a heat filter that is missing or incorrectly installed?
Maybe too high a wattage bulb installed?
Cut a corner off a filter and use a heat gun or hold it close to a lamp t see just what kind of temperature it will stand without damage - this will give you and idea of what is going on inside the enlarger.
I've used these filters in Beseler B23 B45 & Omega D2 with 75w lamps in communal darkrooms and have never seen what you describe.
It obviously sounds like a heat damage issue:
Our filters are very robust ( we test every batch ) but they can obviously be damaged by prolonged exposure ( such as an enlarger left on focus ). We have not changed anything in the manufacturing
Since you are a community darkroom, please PM me your address and I will post some replacements
to you free of charge. I guess you need 8.9cm square, if you need 15.2's make sure you let me know.
Simon ILFORD photo / HARMAN technology Limited :
I always put the filters in the slot below the condesor, for 35mm position I leave the filter on top.
If the darkroom users are putting the filter on top of the condensor for 2 1/4 or 4x5 setting you will indeed burn the filter very fast.
If the filters are kept away from the bulb then there should be no problem , I change them once a year.
Sponsored Ad. (Subscribers to APUG have the option to remove this ad.)
Dear Simon, thank you infinitely for your kindness... I'll do that, although I still have to find a way to avoid this happening again...
Dear Dave, Simon, Bob, I also guessed a heat shock resulting to this damage (although I do not think someone left the bulb burning for such a long time). The problem is that the enlarger head came in a box already almost completely assembled (it just was in three pieces) and there was no heat filter there to place anywhere... the filter drawer is where the manufacturer put it, so I cannot do much to change this... do you think that Kaiser made such an error as to place the filter drawer at the wrong place ? The lamps were included in the package I opened myself, I only had to screw them on the enlarger head's socket...
I surely will take care to inform everyone not to leave the lamp on for a prolonged period of time, at least not with the filter in place, hoping this will resolve the problem...
Thank you all for your help.