Jobo Expert Drums

[jon.oman]

Okay, I looked at as many of the messages here as possible, but I still do not know how these drums work! I know that there are a number of cylinders within the drum where the film is placed. Are these cylinders ribbed? Do they have holes in them to allow the flow of chemistry, or is the chemistry only admitted through the ends? Since such little chemistry is used, I assume that a piece of film is only immersed in the chemistry when its cylinder is at the bottom of the roll?

Can someone explain how these work, and maybe provide images of the inside of the tanks to illistrate how they work?

Jon

[Greg Blank]

Basically an Expert drum looks like the chambers of a revolver, closed at the bottom end open at the top loading end. The 3010 drum has a defined ridge that seperates two 4x5 sheets per tube. So you can load ten sheets into 5 cylinders. The other drums 3006&3005 are only six and five sheets. The top of these drums is closed to light by the drum lid but allows chemicals to transfer from the top cylinder into the downside cylinder as the drum passes what could called zero orientation.

Additionally the space around each cylinder is hallow and the bottom of the drum is vented to except heated water so the drum is evenly warmed are all the tubes.

Okay, I looked at as many of the messages here as possible, but I still do not know how these drums work! I know that there are a number of cylinders within the drum where the film is placed. Are these cylinders ribbed? Do they have holes in them to allow the flow of chemistry, or is the chemistry only admitted through the ends? Since such little chemistry is used, I assume that a piece of film is only immersed in the chemistry when its cylinder is at the bottom of the roll?

Can someone explain how these work, and maybe provide images of the inside of the tanks to illistrate how they work?

Jon

[jon.oman]

Greg,

Thanks for the information. Are each of the cylinders the same diameter throughout their length, or do they get slightly larger toward the center of their length, and then get smaller towards the other end? Sort of like a barrel?

If there are no ribs in the cylinders, how can the anti-halation backing be removed from the film? Doesn't the film stick to the surface of the cylinder when wet?

Finally, do most people use a tempering bath with their roller base with these tanks? Or do they just have a roller base on a table?

Jon

[jon.oman]

One more question, how do you remove a sheet of film from its cylinder? It seems that might be a 'sticking' point!

Jon

[jim kitchen]

Dear Jon,

This device is a fabulous tool to use for myself, and many other folks within the group, where they are extremely easy to use, but the lid can be a chore to remove periodically if you do not have the unit's foot pump...

I tend to heat the lid with very hot tap water prior to popping the lid with the foot pump, where the lid gently pops off the top of the drum, after two or three pumps. That said, the film's surface is completely immersed within the chemical solution as the film is processed, when the film is at and, or near the bottom of the drum's rotational cycle.

The film is removed very easily at the end of the development process, and the film does not stick to the tube walls, especially if one happens to use Photo-flo as the last step in the development process.

You will get good advice from every user, so take notes...

jim k

[Ron Marshall]

Easy to load, easy to remove film, low chemistry volume. I hand-roll mine, and if the air temp is close to the dev. temp, then the dev. temp. doesn't vary signifigantly through the cycle.

But now they are pretty pricey, even used.

[Sal Santamaura]

...Are each of the cylinders the same diameter throughout their length, or do they get slightly larger toward the center of their length, and then get smaller towards the other end? Sort of like a barrel?...

Larger toward the center, exactly like a barrel.

[Greg Blank]

The tubes are very slightly tapered, the smooth tubes of the 3006(4x5) & 3005 (8x10)
have slight groove that enables the chemicals to reach the anti halation. However I must typically lift the drum several times during process run to cut down on problems of not washing it out. I find pulling the film by one edge and wiggling it will make removal easier.

Greg,

Thanks for the information. Are each of the cylinders the same diameter throughout their length, or do they get slightly larger toward the center of their length, and then get smaller towards the other end? Sort of like a barrel?

If there are no ribs in the cylinders, how can the anti-halation backing be removed from the film? Doesn't the film stick to the surface of the cylinder when wet?

Finally, do most people use a tempering bath with their roller base with these tanks? Or do they just have a roller base on a table?

Jon

[dsphotog]

To help the processed film sheets come out easy, I remove the lid, then fill the drum with water.

[jon.oman]

Thanks everyone for the information and usage tips!

Jon