Water temperature for FB prints

[NB23]

I always use hypo clear, then selenium 1:20 and then wash for 1hour in a ZoneIV 20x24 washer (or 11x14). I wash with water that's 20c to 30c with an understanding that the warmer the water the better the wash with a personal upper limit of 30c.

I recently read in an Ilford brochure that the washing should last 1 hour but the water should only be above 5c degrees. Is this true? That would be marvelous!

 

[RalphLambrecht]

the warmer ,the faster the washbutabove 27C you risk damage to the softening emulsion..5C may well take an hour to wash

 

[NB23]

This makes me very curious. If a print takes 1 hour to wash in 5c water, then it should take only a few minutes in 25c water, logically.

Is there hard evidence that 5c water can wash a FB print efficiently? This would be a huge energy saver in the winter time. I often empty my hot water tank and then the pipes can freeze when it's -15c outside. A huge problem when it happens.

 

[Sal Santamaura]

...I recently read in an Ilford brochure that the washing should last 1 hour but the water should only be above 5c degrees...

I suspect you misread that Ilford document. It most likely instructed that the wash water should be within 5 degrees C of the processing solution temperatures, not "above 5 degrees C."

 

[gleaf]

Recheck the context of the 5 degrees. Isn't that the preferred limit for wash above process temperature. Large temperature difference between baths can reticulated (clump) the grain structure.

 

[NB23]

I'll have to find that piece of paper...

 

[miha]

Page 2, WASHING: http://www.ilfordphoto.com/Webfiles/200621111117720.pdf

 

[Sal Santamaura]

I suspect you misread that Ilford document. It most likely instructed that the wash water should be within 5 degrees C of the processing solution temperatures, not "above 5 degrees C."

NB23 has read it correctly.

Ilford says the following regarding FB paper washing:

-After fixing at 18-24C (65-75F), wash at a temp above 5C/41F for the time indicated (usually 60min without a washaid) depending on the paper...

I stand corrected. Five degrees C is awfully cold!

...Kodak gives similar guidance:

-After fixing at 18-24C (65-75F), wash at a temp of 10-30C (50-86F) for the time indicated (usually 60min without washaid/hypo clear)...

Ten degrees C seems a bit more reasonable. Perhaps I had Kodak's guideline on the brain.

 

[RalphLambrecht]

This makes me very curious. If a print takes 1 hour to wash in 5c water, then it should take only a few minutes in 25c water, logically.

Is there hard evidence that 5c water can wash a FB print efficiently? This would be a huge energy saver in the winter time. I often empty my hot water tank and then the pipes can freeze when it's -15c outside. A huge problem when it happens.

I've seen several test reports,which clearly shoe that FBpapers wash to archival limits within 30-60 minutes in 5Cwaterif an alkali fixer and/or HCA was used prior to washing.one of thse tests was conducted by the owner of SilverPrint in London.His name escapes me at the moment. I cannot verify his results,because my tap water never gets this cold.

 

[jeffreyg]

My wash water with our home water system and AC running is in the 23 - 25c range. I use a HCA before washing and wash for 60 minutes. I would think, although I have never studied the subject, that the volume of the washer, time of wash and the flow rate might have more influence on thorough washing than the temperature.

http://www.jeffreyglasser.com/

 

[RalphLambrecht]

My wash water with our home water system and AC running is in the 23 - 25c range. I use a HCA before washing and wash for 60 minutes. I would think, although I have never studied the subject, that the volume of the washer, time of wash and the flow rate might have more influence on thorough washing than the temperature.

http://www.jeffreyglasser.com/

No,time and temperature are the significant variablesFlow rate must justbe high enough to keep the wash water from equalibrium.higher flow rates don't do any good because,print washing is a simple diffusion process.another variable is water hardness.the harder ;the betterinterestingly enough.

 

[fotch]

This makes me very curious. If a print takes 1 hour to wash in 5c water, then it should take only a few minutes in 25c water, logically.

.....

Logical only if water temperature has an influence on results. Apparently that is not the case. Good to know.

 

[NB23]

As does the water flow

 

[MartinP]

Unless one has a very clever pressure-controlled chamber, temperatures under zero are not going to help the exchange of water near the print surface, so the temperature has some effect.

The washing is a diffusion process, not a chemical reaction. Using HCA at a very cold temperature will reduce it's effectiveness though, as that is based on reacting with the fixer by-products to produce a more soluble (and hence more easily removable) end result.

 

[fotch]

Fotch, water temp does have an effect.

So, you have info agreeing with the statement "If a print takes 1 hour to wash in 5c water, then it should take only a few minutes in 25c water, logically. " ?

 

[fotch]

In my response to NB23 I said that temperature has an effect, so the broad logic holds, but that from a diffusion perspective it cannot be assumed to be linear. So while washing should take less time at 25C than at 5C, how much less is not a simple matter. It would require testing.

The evidence we have for temperature have at least some effect is in the instructions from both Ilford and Kodak when a hypo clear and shorter washing times are used. Both companies recommend a wash temperature of 18C-24C.

Got it. So, it is the hypo clear that is temperature sensitive?

 

[RalphLambrecht]

Got it. So, it is the hypo clear that is temperature sensitive?

No, the washing process itself,being partially a chemical process is temperature sensitive.HCAjust prepares thr residual fixer and its silvercomplexes to wash out easier by dissolving themfurther. I'm notaware of any studiesin regard to HCA efficiency at different temperatures, but this may warrant a detailed test!