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Ilford FP4 Plus, Red Filter and Development Times

AnalogueNewbie

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35mm
Hi,

Having looked around what looks to be a great site I thought I'd make my first post.

I went out today and shot some landscape pictures on a roll of FP4 Plus using a red filter. I used exposure compensation of plus one following some advice from a quick google search, however I'm now not sure whether this is correct. Is there anything I can do when developing the film to improve my results i.e. pictures with nice dark skies and vibrant clouds.

I'll be using D-76 1+1

Cheers
 
Just use the recommended development time (by the manufacturer). It will be a good starting point. If your negs turn out a bit flat, you'll know you can increase development time by 10...20% next time, and if they are too contrasty, you know to decrease development time by 10...20%.

There are many different "red filters" and they need different compensation depending how dark they are. If it's a dark filter, then you have probably underexposed and might want to increase development time a bit. If it's light red, then you are fine at the nominal starting point.
 
If you relied on TTL metering, your camera may not have adjusted enough for the needed exposure. Some cameras can only add 2 extra stops of exposure. If you think you have exposed properly, then develope normally. Make notes of the procedure, and adjust exposure on the next roll accordingly. Like tim k, I meter then add 3 stops more exposure. This only works on manual mode(you shouldn't be shooting on auto mode anyway).
 
In camera TTL metering through filters is always uncertain. You never know if the camera meter, often notoriously bad anyway, is getting you even in the ball park. With light colored filters, the problem isn't usually very severe and you can easily get away with using the in-camera metering system. But when you get to the darker filters, like a red #25, the in-camera meter can get dicey. With a lot of B&W films, the recommendation is to add 3 stops of exposure when using a red #25. Most of the in camera meters I use regularly, tell me that I need only 2 to 2.5 stops, and guess what, that's not enough. Do yourself a favor. See the manufacturer's recommended exposure compensation for your particular film and filter combination. Take your best meter reading without the filter, then apply the recommended filter factor. I guarantee it will work. Unfortunately, Ilford doesn't publish filter factor recommendations in the FP4+ fact sheet, so your starting point would be the filter manufacturer's suggested filter factor. Failing that, the filter factors published by Kodak for Plus-X work well. Find them on page 2 of this document.
 
Last edited by a moderator:
3 stops plus exposure for a 25A red filter is what I always use.
 
Hi,

Thanks for the help. I have the negatives just finishing up drying so hopefully should be able to see how they have turned out shortly. I notice the negative is still quite dark in the sky area, so not quite as i'd hoped. But we'll see.

Cheers
 

The filter factos ARE published by Ilford, most of them anyway:

Dead Link Removed
 
tim k said:
I add 3 stops with my red.
Click to expand...

Me too.

In theory the film will be under-exposed by a couple of stops. An extra 50% of development time* will compensate but better to get the exposure right to begin with.

(* I usually add 20% - 25% per stop).


Steve.
 
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