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-   -   Times too short on Devere 504 (http://www.film-and-darkroom-user.org.uk/forum/showthread.php?t=13591)

Faraz 15th January 2021 09:26 AM

Times too short on Devere 504
 
I recently got a 504 mark IV and have started using it. I'm finding the exposure times are too short and I have to use sub-optimal aperture as a result. At f32 (my 150mm lens goes to f45) my time is 7s on Grade 00 and 2s on grade 4. Not much time then for dodge/burn etc.

I'm printing 4x5 negatives on 8x10 paper.

How I can increase times ie. reduce brightness of the enlarger? My negative density is not specially thin though I have not measured it. I'm not sure if I can use lower wattage bulbs or add a acrylic sheet to the mixing box.

Any ideas appreciated

thanks

B&W Neil 15th January 2021 10:24 AM

Quote:

Originally Posted by Faraz (Post 137759)
I recently got a 504 mark IV and have started using it. I'm finding the exposure times are too short and I have to use sub-optimal aperture as a result. At f32 (my 150mm lens goes to f45) my time is 7s on Grade 00 and 2s on grade 4. Not much time then for dodge/burn etc.

I'm printing 4x5 negatives on 8x10 paper.

How I can increase times ie. reduce brightness of the enlarger? My negative density is not specially thin though I have not measured it. I'm not sure if I can use lower wattage bulbs or add a acrylic sheet to the mixing box.

Any ideas appreciated

thanks



Which light head / mixing box are you using ?

Neil..

Faraz 15th January 2021 10:32 AM

It's the Mark 4 light head with 2 bulbs and the 4x5 mixing box.

Terry S 15th January 2021 11:29 AM

Faraz, if I recall correctly, in a not so old previous post, from someone with a similar problem, there were numerous ideas suggested - can anyone remember the link?

The one suggestion that I do remember though, was putting some neutral density lighting gel between the light and the negative, if that's possible with your enlarger? Just looking, it's not expensive and looks easy to cut to size.

NOTE: I have just found an ebay seller who sells a set of 0.3, 0.6 and 0.9 sheets, that would fit the purpose, for just 5.40:

https://www.ebay.co.uk/itm/3-sheets-...8AAOxycD9TVYcI

Terry S

Faraz 15th January 2021 11:54 AM

Thanks for the suggestion Terry. I was thinking about this but was not sure.

I've used ND filters in combination with frosted acrylic before on a smaller enlarger they seemed to interfere with the contrast filtering. In fact almost nothing would print in grade 4-5 despite seeing the image projected. I used a square 1.5mm filter designed for a camera, perhaps a thin film filter would be better.

I think this is worth a go.

mpirie 15th January 2021 11:54 AM

Just what i was about to suggest too Terry....add ND gels above the neg.

If you can buy 0.3 sheets, you should be able to add one or more to bring the times up to an acceptable level.

Mike

PS. You could try one of your camera ND filters below the lens to see if it'd work.

Faraz 15th January 2021 11:58 AM

ordered the Nd gel! I'll try this first and see how it goes

Bill 15th January 2021 01:41 PM

I have a Mk IV head and that only has one bulb. As far as I know the 2 bulb version is the Mk V. It is possible in the same fitting to get 200W bulbs instead of the 250W normally fitted. That may help.

Martin Aislabie 15th January 2021 04:20 PM

I have permanently dialled in 50CC of Y + M + C to give a ND filter on 504 Mk4 to combat the same problems of very short exposure.

You could dial in even more if you needed to - as long as you add the same amount of each.

Then, if I have a very selective enlargement from a Neg and my exposure times are getting long, I use the white light lever of knock them all out together - but I never touch the dials.

It works for me but YMMV

Martin

Bob 15th January 2021 05:04 PM

What's all this with people getting too-short times? I am insanely jealous!


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