Where to start for an 8x10 enlarger?

[Morten]

Top of durst 138 after the top of the colour head is removed. this is where the light mixing boxes normally sist.. will just act as stiff "metall bellows" when in 8x10 configuration :-)

[xkaes]

Attachment 173160Attachment 173161

Did the images get there?

First image is the current set up, second image is the complete colour head where I removed the top part.. will post image of the light opening..

And I thought MY life was complicated!!!!!!!!!!!!!!

[Morten]

And I thought MY life was complicated!!!!!!!!!!!!!!

Consider this an engineering mock-up hopefully the finished version will be more polished and simple looking on the outside.

[Luis-F-S]

So do you plan to offer the LED light source, or are we on our own to figure that out? The rest of the stuff can be made out of plywood given the dimensions. L

[Morten]

Will post pictures of the LED and circuit diagram later today. This is the design which gave me the idea that a 8x10 extension could be possible. http://www.jbhphoto.com/wp-content/u...Printing03.pdf

[Pere Casals]

Will post pictures of the LED and circuit diagram later today. This is the design which gave me the idea that a 8x10 extension could be possible. http://www.jbhphoto.com/wp-content/u...Printing03.pdf

Nice !!!

This is a nice practical solution, having 8x10 enlarger can be a challenge, but this solves it.

Just thinking that some bolts can be used in the "suport of the negative holder" to ensure a convenient micro adjustment of the alignment.

And also thinking that red leds (activated independently) can also be included to project a red light image on the paper, to frame conveniently, this would substitute the under lens red filter that enlargers have.

[Morten]

Will post pictures of the LED and circuit diagram later today. This is the design which gave me the idea that a 8x10 extension could be possible. http://www.jbhphoto.com/wp-content/u...Printing03.pdf

Two circuits for the green and blue LEDs, given the voltage for each LED. For the Red LEDS I did put 9 in series, (voltage over the Red LEDs are less than for the Green & Blue) expected to have to reduce to 8 or 7 LEDs. But works OK. The Red LEDs are used as safelight with Red only, but also for full focus light where alle LEDs are on.
Link to Circuit diagram https://www.circuitlab.com/circuit/2...d_durst138_r0/
Currently plan to build a smaller LED head for 5x7 and smaller negatives, if the light output is to low.

[Morten]

Just thinking that some bolts can be used in the "suport of the negative holder" to ensure a convenient micro adjustment of the alignment.

And also thinking that red leds (activated independently) can also be included to project a red light image on the paper, to frame conveniently, this would substitute the under lens red filter that enlargers have.

Yes, will include that in the final version, currently the "negative holder" is just a picture frame with single glass, was expecting newton rings, but none so far. (Now they will show up later today! )
Yes, the Red LEDs are used as you describe..

[Pere Casals]

Yes, will include that in the final version, currently the "negative holder" is just a picture frame with single glass, was expecting newton rings, but none so far. (Now they will show up later today! )
Yes, the Red LEDs are used as you describe..

Just let me add some thoughts for the 8x10 enlarging I'm also building.

I'm also a PCB designer but for this project I'm to rely in comodity components.

I will place amp meters in each color channel to be sure that the particular channel power can be known at any time from electrical parameters:



$1.48 each: https://www.ebay.com/itm/DC-0-200V-1...YpGl7eAgMwPm1A

Then I would use 1 to 4 RGB LEDs of 100W each, this is a large amount of visible light power, for the moment one alone, each LED should deliver like 800w hallogen or more.



This $5 each: https://www.ebay.com/itm/10W-20W-30W...PZMATlbVpxUNDw


Then I would use a buck converter to adjust channel power that is to be seen in the 3 Ampmeters, for calibrations



$3.3 each: https://www.ebay.com/itm/DC-DC-Buck-...AAAOSw241YlezB

... and a detail for refined pure distinction, guitar tone knobs of a reputed brand stile



$5: https://www.ebay.com/itm/3sets-9-Pcs...4AAOSwstxU5Cnz

In this way I won't need to develop anything for the moment.

Also I'm considering using the fresnel from a transparency projector bed to make it work like a condenser enlarger instead difuser, this is to have high efficiency to throw all light by the lens.

I'm considering not mixing green and blue light during exposure, just making 2 exposures of different adjustable times (split grade printing), in this way one can burn/dodge locally when doing the low or high contrast exposure to have local contrast control.

Just telling my thoughts for the case it can be useful (or not)

Also I'm working in a 8x10 negative carrier that has a clamp in each end, to tension te negative and to ensure flatness without glass... to be 3D printed with some metal parts to ensure flatness...

Regards


Regards

Just telling my ideas...

[Morten]

Just let me add some thoughts for the 8x10 enlarging I'm also building.

I'm also a PCB designer but for this project I'm to rely in comodity components.

I will place amp meters in each color channel to be sure that the particular channel power can be known at any time from electrical parameters:



$1.48 each: https://www.ebay.com/itm/DC-0-200V-1...YpGl7eAgMwPm1A

Smart!