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 ?