LPL 7451 4x5 Enlarger - problem printing 35mm

scrufftie · Dec 9, 2022

I have an LPL 7451 4x5 Enlarger with Dichroic Colour Module. I have been using this quite happily for a while for both 4x5 and 120 printing using 150mm and 80mm lenses respectively.

I wanted to try some 35mm printing so I bought a 50mm lens and have run into a couple of problems.

Firstly, I struggled to get focus when printing on 10x8 paper with the bellows at min. and had to resort to reversing the lens board to seat the lens closer to the negative carrier.

The other problem is that my exposure times are much longer, more than 60secs at f/5.6. If I print any larger, I will really struggle.

Where am I going wrong here? Is this enlarger just not suited to 35mm printing or is it user error?

awty · Dec 9, 2022

80mm lens will be fine for 8x10 and smaller print.
You need a recessed lens board to use a 50mm lens.
Can you use a more powerful bulb or faster lens.

scrufftie · Dec 9, 2022

Thanks. Lens board is reversible so am using it recessed. Lens is f/2.8. I guess I could use it at f/4. I just wanted to be sure I wasn't doing anything wrong. I'll explore the option of a more powerful bulb.

Frank53 · Dec 9, 2022

scrufftie said:
I have an LPL 7451 4x5 Enlarger with Dichroic Colour Module. I have been using this quite happily for a while for both 4x5 and 120 printing using 150mm and 80mm lenses respectively.

I wanted to try some 35mm printing so I bought a 50mm lens and have run into a couple of problems.

Firstly, I struggled to get focus when printing on 10x8 paper with the bellows at min. and had to resort to reversing the lens board to seat the lens closer to the negative carrier.

The other problem is that my exposure times are much longer, more than 60secs at f/5.6. If I print any larger, I will really struggle.

Where am I going wrong here? Is this enlarger just not suited to 35mm printing or is it user erro

There are different mixing boxes. One for 4x5, the other for 6x6 / 35mm.
If you use the one for 4x5 printing 35mm, you get very long exposure times. You could try KHB, Secondhanddarkroom or Ebay.

Frank53 · Dec 9, 2022

There even seems to be a 35mm mixing box, but the 6x7 is fine for me for 35mm.

bdial · Dec 9, 2022

As you learned, using the board in the recessed orientation is necessary for a 50mm lens, so far as I know, this is by design.
I only have a 4x5 mixing box on mine, and my exposure times for 35 mm aren't significantly longer than other formats. Maybe your bulb is not up to par?
Another thought is that you may accidentally have the light attenuating filter in place.

scrufftie · Dec 9, 2022

Frank53 said:
There are different mixing boxes. One for 4x5, the other for 6x6 / 35mm.
If you use the one for 4x5 printing 35mm, you get very long exposure times. You could try KHB, Secondhanddarkroom or Ebay.

Thanks. I have just spoken to secondhanddarkroom and they suggest a mask in the mixer box

Patrick Robert James · Dec 9, 2022

As others have mentioned, it would really be best to pick up the 35mm mixing box. The medium format box is pretty rare since very few people bought one- the 4x5 box being more than good enough for medium format. The 35mm box brings down your times dramatically since it funnels all the light through a smaller diffusion box internally and has a condenser. I even use it to enlarge Minox negs and get respectable times. They are pricey though. I think it is worth it. As an aside, my 4550 gives the best image quality of any 35mm enlarger I've ever used. Better than my Leitz Focomat 1c even. Not as convenient, but better.

scrufftie · Dec 9, 2022

Patrick Robert James said:
As others have mentioned, it would really be best to pick up the 35mm mixing box. The medium format box is pretty rare since very few people bought one- the 4x5 box being more than good enough for medium format. The 35mm box brings down your times dramatically since it funnels all the light through a smaller diffusion box internally and has a condenser. I even use it to enlarge Minox negs and get respectable times. They are pricey though. I think it is worth it. As an aside, my 4550 gives the best image quality of any 35mm enlarger I've ever used. Better than my Leitz Focomat 1c even. Not as convenient, but better.

Having tried a mask, I think you're right. If I'm going to print 35mm, I'll need to get one. from what I have seen, it's a condenser lens, which replaces the diffuser on the box. now, to track one down....

scrufftie · Dec 23, 2022

As a quick post script, I found a diffuser with condenser lens for 35mm printing. Works a treat but I could probably have bought a small 35mm enlarger for the price….

LPL 7451 4x5 Enlarger - problem printing 35mm

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