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  #11  
Old 14th July 2020, 08:05 AM
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Originally Posted by Lostlabours View Post
You can easily confuse what's meant here, in the linked thread Soft working means in terms of soft contrast where choice of a Soft working developer came reduce a paper's contrast by around a Grade or more.

The term Contrast developer, or High contrast developer is used to denote the opposite where the developer can increase a paper's contrast by a grade by or more.

The term "Hard working" was used to denote high and consistent throughput, a developer that wouldn't collapse during a printing session.

An example would be D163 which was Kodak's main paper developer here in the UK (Dektol/D72 was the US alternative and introduced here much later). Bot D163 and D72 are MQ developers and because of the Metol don't have a particularly high throughpu, with papers there's a gradual build up of free Bromide as a result of development and this inhibits the developing action of Metol slowing development to the point where times increase significantly and it then becomes ineffective.

If you switch to a PQ developer like ID-62/PQ Universal (or Kodak Liquid Dektol) using Phenidone or Dimezone instead of Metol you find tray life and capacity are vastly superior. Phenidone isn't inhibited by Bromide build up.

It's similar with commercial film developers ID-11/D76 is inefficient in machine processors (it was used) because you need to use a bleed system where you remove working developer and add sufficient replenisher to keep the bromide level under control, but eventually it collapses. Ilford introduced Autophen a PQ version of ID-11 and it could be replenished by topping up which is far more efficient and economic, plus the developer could be replenished for far longer, in one lab it was years. So this is another example of a Hard working developer.

When I began printing in the mid to late 1960's a tray of D163 would last less than a 2 hour session, PQ Universal will last a full day session with no deterioration.

Ian
Ian
Thanks for that Ian. nicely explained.
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  #12  
Old 14th July 2020, 11:11 AM
Tony Marlow Tony Marlow is offline
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Whilst mention of PQ has been made I have seen in Ilford's technical information that the minimum time for RC prints in PQ is 2 minutes which hasn't appeared on the leaflet in the paper box. MG is still 1 minute.

Tony
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Old 14th July 2020, 01:08 PM
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Originally Posted by Tony Marlow View Post
Whilst mention of PQ has been made I have seen in Ilford's technical information that the minimum time for RC prints in PQ is 2 minutes which hasn't appeared on the leaflet in the paper box. MG is still 1 minute.

Tony
Surprising that it is not in the paper data sheet as I have looked at a copy of the Ilford Technical sheet for paper developers dated 2004 and it is in there. I am in the process of changing from MG developer to PQ and have been giving 1m 30s so I need to change my way of working.

Thanks for mentioning this Tony.

Bill
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