Enlarger focussing aid for large prints

[Marizu]

What kind of focussing aid do I need to check that my enlarger is straight for large prints?
The one that I have only realy works in the centre portion of the image.

Thanks in advance,
Marizu

[michaelfinch]

Many years ago when I was setting up my enlarger I was advised that the first step was to ensure that the neg carrier, lens board and baseboard were all parallel. I did this by clamping a 10in x 12in glass sheet in the neg stage and then measuring from each corner of the glass to the baseboard and then across the diagonals to ensure all was well. I remember making a few small adjustments. It was a wee bit fiddly but it worked. Most good LF/MF enlargers are well engineered (mine is a Beseler 45MX with an Ilford 500 Multigrade head plus a colour head; well enough engineered but not as good as some) and adjustments can be made.
One problem that might be encountered is illumination fall-off at corners/edges and these days I doubt if my eyes would pick out the full detail even with a magnifier. A high quality lens will help and they are not expensive these days if bought used. Hope this helps.

[lostlandsuk]

What kind of focussing aid do I need to check that my enlarger is straight for large prints?
The one that I have only realy works in the centre portion of the image.

Thanks in advance,
Marizu

Hi Marizu - I get the feeling you're talking about two different things here. Setting up your enlarger for parallelism in all planes is different in a way to finding a grain focusser for checking the corners of your prints. If you want to study it to the nth degree - Barry Thornton went into the whole thing in immense and useful detail in his book Edge Of Darkness.
If your enlarger is level and parallel and it is just for checking whether your negative carrier is holding your neg straight and the whole thing is in focus on the enlarging paper, then there's a few things: The Peak focus finder will enable you to focus on the grain at the edge of the print; the Nova Hocus Focus I think also does the same thing.
Most focus finders like the Patersons and the Scoponet will only work on the centre portion of the image.
Cheers
Phil

[IanG]

The Nova Hocus Focus is a great little focus finder, I find it ideal even when enlarging 10x8 Adox/EFKE 25 negatives where the grain is so fine it virtually invisible

Ian

[Emmanuel Bigler]

Another problem with manually-focusing enlargers is that at large manifications, the distance between the head and the base boad makes impractical to rotate the focusing knob manually while checking with your eye looking inside the focus finder seating on the board.
On my AHEL 12, I bought a device supposed to "extend" the focusing knob, it is a kind of flexible arm + a second knob that you attach to the main knob.
Regarding the focus finder itself, I've been happy with the scoponet for 3 decades, but, agreed, you cannot check for the proper focus in the corners.

[IanG]

Another problem with manually-focusing enlargers is that at large manifications, the distance between the head and the base boad makes impractical to rotate the focusing knob manually while checking with your eye looking inside the focus finder seating on the board.

That's why the focus adjustment on a modern (60's onwards) De Vere is done from a wheel at the front just below the baseboard, as is height adjustment

Ian

[lostlandsuk]

Totally agree with Ian - once you've used the wheels on the Devere, there's no going back! I love my 504
Phil

[apochromatic]

I still have a 'tall' focus scope which I used for huge enlargements with a wall-mounted DeVere. Even with this I almost had to pop my shoulder out of joint to reach back up to the focus wheel! I think it's made by Patterson but it must have been a rare beast as I've never seen another: its stands about 30cm high