View Full Version : HP Combi Plan - What Volume?

Rafal Lukawiecki
21-Feb-2008, 08:50
I've been using my cute HP Combi Plan T for 5 years on and off and I am happy with it, but I have never resolved the curious matter of the recommended volume of liquid that it requires for 4x5s. The inside of the lid states that it needs 1250ml or 36 fluid ounces. But 36 fl oz is only 1064ml - nearly 200ml less.

Interestingly, the advice on the inside lid of the tank for other formats is fine, that is the metric measures convert reasonably correctly to ounces - except for the 4x5 size.

Now that I live in the country and have a septic tank I collect and dispose of used chemicals at a recycling centre. Thus the problem of volume: I could just about put 1064ml into many used "1l" plastic bottles (milk, drinks etc.) but for 1250ml I need to use bigger bottles, which I just don't generate enough of in my household - and use the ones I do for my paper chemistry (2l normally).

Is the 36 fl oz vs 1250ml advice my tank gives me another example of how US differs from the rest of the world?


PS. I've been using about 1280ml because it's easier for me to mix 110HC that way (40ml of concentrate for dilution B) and stays on the "too much" side. I guess I have never been chicken enough to try less in case I got my negs damaged.

Bjorn Nilsson
21-Feb-2008, 09:38
Taking a closer look inside the lid it states that 1250 ccm is needed for "10 x 15 cm". 10X15cm corresponts to about 4x6 inches. You are correct about the 36 ozs. for 4X5 inches. You seem to read the two tables as one, when they in fact are two separate tables. The european size in the left table and the "strange one" in the right table. ;)
It's quite funny how a piece of equipment made in Sweden does have german and english instructions printed (moulded into) on it, but nothing in Swedish.


Rafal Lukawiecki
21-Feb-2008, 09:46
Thanks! I never thought of reading this table that way - I just assumed it was a US and a metric "column". In that case I guess I should be safe with 1064ml for 4x5.

I wonder who does 10x15cm.


Bob Salomon
21-Feb-2008, 09:51

Actually that isn't quite what is on the inside of the tank lid.

On the left side there are the quantities required for metric sheet sizes and 1250 ccm are for 10x15cm sheet film. On the right side are the sizes for english sizes hence 36 oz for 4x5" film.

Now you might wonder why on the top of each column is the german word for volume required is on the left side and the english solution required is on the right side.

A bit of history.

The Combi Plan is not a US product. It was invented in the 50s by a man named Krause in Germany and for many years was sold by him as the Krause tank. He made Combi tanks for 35mm and 120/220 as well as 45 and 57 in Germany. As Linhof was one of the larger sellers it was also called the Linhof Combi system. In the 70s Herr Krause sold the system to Gepe and it was then manufactured in Sweden as the Gepe CombiPlan system. In the 80s, due to a conflict with a competing processing system with one of Gepe's distributors Gepe sold the CombiPlan system to HP Marketing Corp. in the USA and it then became the HP CombiPlan system. After 1983 we decided to discontinue the 35mm and roll film tanks, the 57 system and the 45 CombiPlan L system and kept manufacturing the HP CombiPlan T system T for inversion agitation).

Originally we were manufacturing the Combi system in the USA with the original German tools. But these were not 100% compatible with the molding presses used in the USA and we transferred the production of the tank back to a Gepe owned factory in Sweden.

So no, the difference in chemistry required are not due to any differences with the USA. They are the original numbers from the original German manufacturer. And the metric quantities are expressed as ccm not ml.

But thank you for pointing it out. Since some of the film sizes listed are no longer current the next time we have to repair the tool we may change the lists completely.

Bjorn Nilsson
21-Feb-2008, 10:11
Now, what would we do without Bob S. on this forum. As always a never-ending source of everything you need to know (and sometimes also the things you didn't knew you needed to know...).
Once again, thank you Bob.


Rafal Lukawiecki
5-Mar-2008, 05:12
Bob, Björn,

Thank you, very much, for your kind explanations and the history of this useful device - fascinating read.

I wonder how "rounded" are the recommended amounts of fluid. I.e. would the 36 fl oz (which is 1.06l) be really needed, or would 1l be OK for 4x5". Visually 1l seems to cover the negs, but I wonder if this has been a tested scenario.


Joanna Carter
5-Mar-2008, 05:47
I regularly use my Combiplan with 1ltr and have had no problems.

5-Mar-2008, 07:15
As I understand it, the liquid is supposed to slosh around when you're inverting, hence one liter of chems.. That's the way I do it and get great results. I also knock it after each inversion cycle 'just in case' I created more bubbles -- purely a religious move.