Temperature control for colour developing and printing

[xtolsniffer]

Hi all,
I've been thinking about making the jump from developing monochrome into developing colour. I've been doing black and white for years but the issue I have is that my darkroom is cold (a shed in my garage, often hovering at around 6 C). I used to have a lovely Grant water bath that I fished out of a skip at the back of a university but it broke last year and the part (an IC) was no longer available, so I've rigged up a water-bath with an aquarium heater and a water pump with is fine up to about 25 C. I've tried putting heaters into the darkroom to get a better ambient temperature but it's hard to maintain a stable temperature. I should be ok with C-41 colour chemistry with a big water bath (I have hot and cold running water), but it's the printing I'm not so sure about. Does anyone have any suggestions as to what they do with temperature control? I could go half-way and just develop and scan, but if I'm going to start developing, I'd like to be able to print as well - it's not so much the final print that's important to me as learning the skills to do colour properly.

 

[pentaxuser]

No less a person than PE prints RA4 at room temp i.e. 20C or so with success. I have done it in a Nova Quad at about 25C

I don't think there is a critical temp for RA4 as long as it is 20C or above and whatever temp you choose can be maintained

Dev at 20C needs 2 mins. I have no idea what the table of temps might be from 20C to 35C. Whatever you can maintain, if it isn't 20C might be a suck it and see in terms of time adjustment but I don't think we are talking X secs is OK and X plus or minus 1 sec is a disaster

pentaxuser

 

[DREW WILEY]

A nice gadget for keeping modest amounts of RA4 chem at stable temp is the Jobo Tempering Box. They turn up used sometimes. I prefer
to do RA4 at 83F.

 

[Wayne]

I'm going to try the PE method when I print again.

 

[sagai]

After much debate I have started to put together a blog to describe the way I do C41 with elementary tools only.
It is not complete yet, however I have some images to share about the process.
It is only for to get the film processed though.
https://plus.google.com/photos/117751586389383036975/albums/6127063135296773873

 

[amellice]

Hi all,
I've been thinking about making the jump from developing monochrome into developing colour. I've been doing black and white for years but the issue I have is that my darkroom is cold (a shed in my garage, often hovering at around 6 C). I used to have a lovely Grant water bath that I fished out of a skip at the back of a university but it broke last year and the part (an IC) was no longer available, so I've rigged up a water-bath with an aquarium heater and a water pump with is fine up to about 25 C. I've tried putting heaters into the darkroom to get a better ambient temperature but it's hard to maintain a stable temperature. I should be ok with C-41 colour chemistry with a big water bath (I have hot and cold running water), but it's the printing I'm not so sure about. Does anyone have any suggestions as to what they do with temperature control? I could go half-way and just develop and scan, but if I'm going to start developing, I'd like to be able to print as well - it's not so much the final print that's important to me as learning the skills to do colour properly.

@ 68F/20C 2 min in Dev, 30 sec in normal B&W stop bath, 2.5 min in Blix. This is with kodak RA chems in trays

 

[DREW WILEY]

RA4 is actually a bit fussy about temperature if you expect reasonably repeatable results print to print. If you can't maintain developer temp
consistently, then you might go thru hell trying to calibrate your colorhead to begin with. Kodak formally publishes recommended time/temp
combinations for RA/RT if you search (I don't have the link at the moment).

 

[mklw1954]

I do RA4 in drums (Cibachrome 8x10 and 11x14 drums on a Uniroller) and Kodak Ektacolor RA4 chemicals at 83F (28.3C) - 30 seconds water pre-wash, 2 minutes developer (no starter), and 2 minutes blix, per Kodak's J39 publication. I have the pre-wash water and chemicals at room temperature, measure out 70 ml (for 8x10s) in 8 oz. spring water bottles and heat them to 83F just prior to adding them to the drum. I use a digital LED thermometer with a wire probe in the bottle and bring it to the right temperature using a pot of hot and cool water. The thin-walled plastic bottles allow for rapid temperature change. The time on the roller allows for adjusting the temperature of the next chemical. The probe is rinsed before inserting it into the next bottle. Originally I used a $20 Extech TM20 thermometer but the response time to temperature change was kind of slow, so I use cheap $3 LED thermometers with a wire probe from China (see ebay) and they work just fine (the probe at the end of the wire is abut 1/2" long, they take a 1.5 V LR44 battery). They are calibrated to a Paterson color thermometer. They might last 6 months to a year but they are cheap. I have done this at room temperatures of 65F to 85F without any change in the times. I use Fuji Crystal Archive Type II paper and the prints are beautiful.

 

[perkeleellinen]

Get a Nova Quad for RA4; easy to find in the UK too.

http://www.secondhanddarkroom.co.uk...-cart-i_shop_here-s-h_processors/?k=27672:5::

 

[RPC]

It is easiest to do RA-4 in trays at room temperature with Kodak RA/RT Developer Replenisher. The developer fumes bother some, for that one can mix developer from scratch chemicals with simple formulas without the smelly, offending preservative with excellent results. Shelf life will be shorter, however.