Hi, forgot about the paper developer. It's Ilford PQ. The paper is ilford multigrade IV RC de luxe.
I believe the light is as neutral as possible. I opened up the head and there are no filters in the way. The bulb sure seem like 75w, I can't look near it for more than a split second with the cover off.
I will check the other things you have all mentioned.
Last edited by kipkeston; 12-13-2007 at 10:04 PM. Click to view previous post history.
You can open the lens aperture a bit. Most of the enlanrger lenses I've been using achieve best image quality when stopped down by only one or two stops anyway.
i have very long exposure times once in a while
sometimes, it just happens (even with negatives that look "normal" )
I use a lot of Kodak C41 black and White films and I find the exposure times to be just under a minute at 5.6 so your times are just one stop off that. Are you using colour masked films
If I remember correctly, the Omegar 50/3.5 is a kit lens that came with some Omega enlargers. I think I have one that came with one of my old enlargers (I'm not at home to verify, so I'm working from faulty memory). If it is, it's not a very good enlarging lens and may be a partial source of your problem by not transmitting the projected light efficiently. If it's the lens I'm thinking of, you probably do get better performance at f/8 than wider apertures.
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Really good 50mm lenses are cheap and easy to come by. What temp is your developer at?..Evan Clarke
Originally Posted by Lee Shively
I've got a Chromega B. I have the manual for it, too. If you don't have one, PM me and I'll xerox you the pertinent pages.
There is no interchangeble mixing box. The "B" is a 6x6 enlarger that will, of course, also do 35mm, but there are no changes to the machine other than the lens.
60 magenta is a lot of filtration. For Ilford MG that is the equivelent of over grade 3 1/2 !!. Have you tried making a print, say, 8x10, without filtration? I would bet that your time will be much closer to what you are expecting. If your prints have next to no contrast without filters (should equal grade 2) then something else is wrong besides the enlarger. This could be exposure, development, bad paper, the variables are many.
As for the enlarger, I hope you got the power supply and the voltage regulator with the kit. The voltage regulator is not critical, I suppose, for B&W, and I don't know IF it makes any difference in light output. The bulb is a 75 watt, 27 volt, part # 471-043 (that may be imprinted inside the lamp housing. There are a lot of these haligen bulbs that look alike, so make sure it's the right one. (EDIT: the voltage regulator - I went back and read the manual - is optional, so shouldn't be pertinent to this discussion.)
The lens might have some haze, too. But all in all, I suspect that attempting to print at a grade between 3.5 and 4 is the crux of your problem. If a filterless exposure was 30 seconds, for instance, dialing in 25 magenta will almost double that, and 60 will likely double it again, and you are at 2 minutes.
Last edited by David Brown; 12-14-2007 at 09:06 AM. Click to view previous post history.
Are you saying that the cyan filter (and presumably the magenta and yellow filters) in color enlargers have substantial neutral density components in addition to their "advertised" colors? If so, this seems a bit surprising to me, but as my own enlarger (a Philips PCS130/PCS150) uses an additive color system, I can't do any tests to check this. Certainly with mine, adjusting "cyan filtration" (really red light intensity) has no discernible effect on B&W VC papers.
Originally Posted by Photo Engineer
In the subtractive color system, mixing all three will give you neutral density (eventually black), in an additive system mixing all three gives you white.
How much ND you get depends on how much of all three are dialed in.
In B&W or color you only use 2 of the three filters at most, unless you actually need to reduce the light output, which would not be a common situation. For example, you are making a very small print, the lens is stopped all the way down, and the exposure is too short.
For B&W, you can use combinations of yellow and magenta to keep exposures consistant across grades, Ilford and Kentmere document the filter combinations for this.
Originally Posted by srs5694
If you look in the Kodak filter books you will see that no filter is perfect. A perfect filter is a rectangle in absorbance or transmittance. So, yes, what I said is true.
In particular, a cyan filter has a lot of green and blue absorption, etc.