enlarger filter

<p>I just bought a Besseler c23 III. It has the V.C. head. It came with a red "safety filter". Just what is the purpose of the red "safety filter"? Thanks. Gus</p>

<p>The red filter was a 'safe light' for paper that was more or less insensitive to the red part of the spectrum (orthochromatic).</p>

<p>Since the B&W paper is not sensitive to red, you can put the safety filter in place and focus your enlarger on a sheet of paper without exposing it. Once you have set your focusing and magnification you can remove the filter and expose the paper. I generally don't use the safety filter but simply focus on a scrap sheet of paper and then substitute the good paper when I want to expose.</p>

<p>Thanks all. I get it now. I too will not use it. I just use a peice of scrape paper.</p>

<p>For critical focus with the enlarger lens wide open or nearly so, be sure to use a sheet of scrap paper that's comparable in thickness or "weight" to the light sensitive printing paper you plan to use. A sheet of photo grade inkjet paper is about right. But if you stop down the enlarger lens the paper thickness is less critical.</p>

<p>In the old days, we just developed a blank page of the same paper and used it for focusing, then you knew the thickness was the same.<br /> It was, of course, critical to mark it on the edge or something so you knew it was not (re-)usable, however. ;)</p>

<p>The red filters were especially useful when not using an easel. You could simply lay the paper on the base board, with the red filter in place you can position the paper where you want it. Another use is if you have a short amount of time for your exposure and you need to dodge a section, you can use the filter to help you set up the dodger in place, turn off the enlarger, move the filter out of the way and then start your timer when you have everything set.</p>