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> Old paper; is fogging the only problem? |
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#1
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Old paper; is fogging the only problem?
I have been very frustrated of late by a box of Ilford MG IV RC satin 16 x 12" paper. Essentially I now know it had lost sensitivity around the edges, particularly on the short sides, so that prints when properly exposed centrally were hopelessly underexposed on the short sides and corners. I assumed this was edge light fall-off, but no matter how hard I burnt in, the poorly exposed area refused to come up.
Exposure measurements through clear film showed edge fall-off from centre was about three-quarters of a stop which I understand is fairly normal. The paper according to the code (see Larry's post in Testing Old Paper thread above) was either made in 2007. or 1999, or 1991. I am pretty sure, but not certain, that I bought it before 2007, so it could have been made in 1999. There was no sign of fogging (which I take to be loss of contrast and/or faint overall greyness). The highlights were as white as the driven snow. I know it had printed normally previously, perhaps 2 or 3 years ago. I was nearing the end of a box of 50, which I eventually finished, kidding myself that I had cracked the problem when I knew I hadn't. Then I started a new box and Bingo! - perfect even illumination, no burning required. Is this normal? It's a new one on me. Richard |
#2
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A new one on me too. I had no idea that a characteristic of older paper was this kind of edge fall-off.
I don't think I have seen this mentioned on other site either where there has been plenty said about the faults of older paper Maybe someone will be able to throw some light on it D: Mike |
#3
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Regardless of the age of the paper, it should not loose sensitivity around the edges in relation to the centre. This sounds like an enlarger problem. Wrong lens, lens plate wrong way round?
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#4
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If the packaging is not completely lightproof then I can visualise the edges suffering first. You say that there is no fault with a new box of paper so the problem must lie with the original. Has the box been subject to undue heat since this could I believe also promote fogging and would tend to effect the outer edges first although why the long sides are not also effected is a mystery to me.
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#5
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Possible chemical fume ingress? I believe that can cause fogging.
It affecting the short sides more would tie in with something happening with the open edge of the plastic envelope. My boxed paper is kept in a cool cupboard with a close fitting door - I made some prints on 10 year old Jessops RC and 7 year old Agfa RC at the weekend and they were all sound as a pound (maybe I should re-word that last bit ) Phil |
#6
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Richard, reading your post again and replies so far, I think some may be a bit confused about your original statement. You state the paper has loss of sensitivity on the sides, particularly on the short sides, not that it is fogged. Is this correct?
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#7
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Isn't loss of sensitivity the first stage of fogging?
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#8
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Dave, if I could put your question the other way round, when flashing printing paper to reduce contrast, although not fogging it as such, it also increases speed slightly by producing inertia within the material. I would suggest that cut off of this inertia is not at the point of the first stage of fogging. However, this may depend on how you assess it, by eye or with a densitometer.
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