Leica V35 Enlarger time calculation

[ericzhu]

I got a V35 enlarger. Here is a little question on the exposure time issue. When the test strip shows that exposure time shall be 8 seconds when the enlarging index is shown 6 on the arm. What's the correct time for the enlarging index of 12? Is it 16 seconds (8seconds*2)? Thanks.

 

[rxmd]

Usually if you double the enlargement factor you have to multiply exposure time by four, because the area of the picture gets larger by a factor of four (double size in dimension X times double size in dimension Y).

 

[ericzhu]

Usually if you double the enlargement factor you have to multiply exposure time by four, because the area of the picture gets larger by a factor of four (double size in dimension X times double size in dimension Y).

I am not sure whether the enlarge index on V35 is the enlarged ratio of dimensions (lengthXwidth). If it is, no need to double calculate it.

 

[rxmd]

That should be easy to see. If the scale is linear, it's the enlargement factor (i.e. four times the time for twice the enlargement factor); if it's logarithmic, it's proportional to the picture area (i.e. twice the time for twice the area). I don't have a Focomat, but usually what's given is rather the enlargement factor.

Philipp

 

[Ronald M]

It is a magnification scale. Double the width and length is four times the area and requires 2 stops more or 4x the time ignoring any reciprocity factors.

4x5 scales up to 8x10 the same way.

Make sure the scale is rotated so it goes to 16x if you are using the 40mm lens. The back side goes to 11 and is for a 50mm lens.

Setting the voltage on the back side of the column base to 120 or 125 will deliver less voltage to the bulb and they will last a long time. A voltage stabiliser will do the same thing. If you are very lucky, yours came with the one that starts the lamps out low and increases to full in a few seconds. They were $400 in 1985 so I did not get one.

Incredable machine. Enjoy

 

[ericzhu]

It is a magnification scale. Double the width and length is four times the area and requires 2 stops more or 4x the time ignoring any reciprocity factors.

4x5 scales up to 8x10 the same way.

Make sure the scale is rotated so it goes to 16x if you are using the 40mm lens. The back side goes to 11 and is for a 50mm lens.

Setting the voltage on the back side of the column base to 120 or 125 will deliver less voltage to the bulb and they will last a long time. A voltage stabiliser will do the same thing. If you are very lucky, yours came with the one that starts the lamps out low and increases to full in a few seconds. They were $400 in 1985 so I did not get one.

Incredable machine. Enjoy

Thanks, Ronald. V35 is a good machine for 135 film, easy to operate. Mine is 220V, suitable to our voltage. What a wonder if it could enlarge full size 6cm*6cm film, which I use for twin-lense rolleiflex.