High base fog, should I worry?

revdoc · Aug 24, 2023

retina_restoration said:
Kentmere has a significant base dye density - it's built in to the film. Have none of you USED Kentmere?? The base density is irrelevant in practice.

Correct! Kentmere films have a grey/blue base, much denser than any other film I've seen. I believe this reduces halation without costing as much as a more typical anti halation layer.

It's not in the image layer, so it's not something that will affect the result, other than making your exposures about one stop longer.

250swb · Aug 25, 2023

Fatih Ayoglu said:
So the question is should I worry about this? If I should what can I do to lower it to the levels of 0.05 like all the charts I’ve been seeing.

Cheers,
Fatih

Forgive me if you've already said what type of fix you are using, I've read through and can't spot it. But if it's something like Ilford Rapid Fix it can literally go off overnight, it works one day then quits the next, even before it starts to smell or look 'off'. It can however be long lasting especially if you use a stop bath which makes the whole thing about going off deceptive.

Fatih Ayoglu · Aug 25, 2023

250swb said:
Forgive me if you've already said what type of fix you are using, I've read through and can't spot it. But if it's something like Ilford Rapid Fix it can literally go off overnight, it works one day then quits the next, even before it starts to smell or look 'off'. It can however be long lasting especially if you use a stop bath which makes the whole thing about going off deceptive.

Hi,

My protocol is, develop, 30 sec stop and then Ilford 1+4 Rapid Fixer for 3-4 mins. I also test fixer before each time I put it in a tank with a scrap film and if the clearing time pass 1:30, then I disregard it. To be honest for 5 years that I have started to develop film, I’ve never seen it took longer than 1:30 to clear the film but sometimes I just prepare a new one because it’s been a while

Bill Burk · Aug 25, 2023

ic-racer said:
In my experience testing, base fog 0.40 eats into the dynamic range of the film. This diminishes latitude.

…

It’s not fog, it’s base anti-halation dye. No impact on image (except the anti-halation properties that make the final picture better looking).

Fatih Ayoglu said:
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PS I have stripped emulsion part of some scrap film, indeed I can get 0.05 to 0.07 density, pure for plastic, which is normal I think. Also I have tested further scrap film, some has as low as 0.2 HP5 120 some has 0.4 K400 35mm

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pentaxuser · Aug 25, 2023

Fatih Ayoglu said:
Is Clorox a bleach technically? Sorry I am in UK and keep googling about it

PS I have stripped emulsion part of some scrap film, indeed I can get 0.05 to 0.07 density, pure for plastic, which is normal I think. Also I have tested further scrap film, some has as low as 0.2 HP5 120 some has 0.4 K400 35mm

All in all I dont think it does effect my printing except the higher the base+fog density, the more exposure it needs to reach max black.

Just a thought but it is always worthwhile to put England after Birmingham Nearly all respondents are U.S. based and there is a Birmingham in Alabama so you'll get U.S. names for chemicals/household goods and U.S. sources as well. If it is clear that you are U.K. based then that gives the U.S. respondents a chance to say what Clorox does or mention the actual chemicals used in it so you can find the U.K. equivalent or at least have a better chance

I hadn't heard of Clorox either

pentaxuser

Fatih Ayoglu · Aug 25, 2023

pentaxuser said:
Just a thought but it is always worthwhile to put England after Birmingham Nearly all respondents are U.S. based and there is a Birmingham in Alabama so you'll get U.S. names for chemicals/household goods and U.S. sources as well. If it is clear that you are U.K. based then that gives the U.S. respondents a chance to say what Clorox does or mention the actual chemicals used in it so you can find the U.K. equivalent or at least have a better chance

I hadn't heard of Clorox either

pentaxuser

And they made it the capital of the State

grain elevator · Aug 25, 2023

MattKing said:
High base density also affects our ability to visually assess our negatives.
That isn't in any way an insurmountable challenge - but it does take some practice.

Yes, and I just find the look of these negatives a bit off-putting, to be honest. Superficial, I know. But i do this for fun and looking at freshly dried negatives is part of the fun. The dark base also doesn't seem to be a very good antihalation measure, I've seem some halation with K400.

pentaxuser · Aug 25, 2023

Fatih Ayoglu said:
And they made it the capital of the State

Yes but our Brum was the "workshop of the world" with a gold quarter, some famous motorbikes manufacturers and the home of the "Peaky Blinders"

pentaxuser

Sirius Glass · Aug 25, 2023

Do the best one can avoiding fog, the work with what you have on the film.

High base fog, should I worry?

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