Philips PCS130 and PCS2000 enlarger masks

thingiverse

Description =========== After leaving my photographic darkroom unused for several years, I decided to do some enlarging; however, I couldn't find the plastic 6x6 medium format masks for my Philips PCS130 negative holder. I could find my 6x4.5 masks, so I used them as a model and created a 6x6 mask set using my 3D printer. For good measure, I looked up the sizes of various other film formats and plugged those values into the OpenSCAD file, then made some more refinements to the model. I'm providing `.stl` files for all of these masks, in case somebody needs them. (The 35mm mask, at least, doesn't closely resemble the official Philips one, which is made of metal and includes alignment pins. My plastic masks work fine in my tests, though.) I also created a slide option, which creates a 51x51mm indentation in which a mounted slide can sit. Color positive papers have been out of production for years -- Ilfochrome since 2011 and Kodak's Ektachrome Radiance since 2003, for instance. Thus, use of a slide mask is likely to interest people using the enlarger for slide copying, creating internegatives, digitizing slides with a digital camera, doing exotic RA-4 reversal processes, or making B&W prints from B&W slides. The `.stl` file for the slide variant includes a 40x40mm image area, which should handle any common format up to 127 medium/square format slides. (The slide mount itself should block unwanted light from the image area out to the slide's edges.) If you need a different image cutout for an exotic slide format, you can modify its size and re-build a new `.stl` file, as described later. Printing This Model =================== You will need to print two copies of this model for each film format you want to enlarge, one to use as the upper mask and the other as the lower mask. Any reasonably solid plastic should work. I used PLA, but PETG or ABS should do fine, too. Black (ideally non-glossy) is obviously preferred. The `.stl` files should be printed aligned as they load into most slicers, with the outermost edges producing modest overhangs (45 degrees or less) and the inner cutout *not* producing an overhang. (The slide-mount variant loads upside-down from this, so that the cutout for the slide prints on top, thus avoiding a nasty overhang.) The 45-degree overhang prints fine on most printers without supports. It's best to print on a very smooth surface, such as glass or a smooth PEI sheet, rather than on a textured surface. The surface of the mask that prints in contact with the print bed will touch the negative, so any roughness could scratch your negatives. If a glass print bed has been chipped, those depressions will result in bulges in the mask, which may prevent the negative carrier from closing, and could damage your negatives, so avoid such areas when placing the mask in your slicer, or file away any such flaws after printing if necessary. You may also need to file the edges to remove anything that might damage your negatives; but if your printing surface is sufficiently even, this shouldn't be necessary. After I printed my masks, I found very fine plastic filaments hanging off the edges. These will be visible in darkroom prints, if they obtrude into the negative area, so be sure to look for such strands with a magnifying glass or loupe, and remove them as necessary. Modifying This Model ==================== You can create masks for film formats I've not considered by adjusting the `negWidth` and `negHeight` variables, then recompiling the model in OpenSCAD or using the Thingiverse Customizer. I found conflicting information online about actual image sizes for some film formats. In some cases I measured actual negatives or my PCS130's 6x4.5 mask, and in other cases I went with what I found online. The `label` variable specifies identifying text that's impressed into the mask. Change this variable as desired for any new mask you create. This label only appears if the `negHeight` variable is less than `43`, which means it's omitted from medium format masks. The resulting text is not very legible, but it's better than nothing. If you want to create a mask for slides, set the `doSlide` variable to `1`, set the `negWidth` and `negHeight` variables to whatever value you need, and recompile the model. Note that the model creates a cutout for a slide of size 50x50mm and a thickness of 1.1mm (all measured from an actual slide), with a little extra slop. (Half the thickness is removed from each mask piece.) If you have slides of unusual size, you can adjust these values with the `slideWidth`, `slideHeight`, and `slideThickness` variables. If you have another brand or model of enlarger and need masks, it's possible that this model can be adapted. The `maskWidth`, `maskHeight`, and `maskThickness` variables set the outer dimensions of the mask. If you're lucky, you can adjust these values to suit your negative carrier; however, the edges of the mask are beveled, and if your negative carrier requires another type of bevel, or some other change, you'll need to adjust the beveling in more detail by modifying the code in the `MakeMask()` module, which is pretty straightforward if you're familiar with OpenSCAD. Using the Masks =============== Once printed, the masks can be used exactly as the original Philips masks are used, by moving the retaining locks in the negative carrier to release the existing masks (as shown in the figure), placing the new ones, and moving the retaining locks to secure the new masks. This must be done on both the upper and lower parts of the negative carrier. Note that Philips' 35mm mask is made of metal and includes alignment tabs. The Philips carrier includes its own alignment tabs that you can use independently of the mask's alignment tabs, so this shouldn't be a problem on 35mm, 126, or larger film formats except for very short negative strips, although the final image or two won't touch the carrier's tabs. The carrier's tabs don't reach far enough to help at all with 16mm film, so you'll need to align 16mm negative strips without that aid. Be sure to use the condensers (for PCS130) or mixing box (for PCS2000), as well as an enlarging lens, suitable for your negative's size. See the Philips documentation for details. If you bought the enlarger used and don't have the original manual, check the scans available at https://groups.io/g/TriOne/files. If you're using a panoramic format that expands the image area relative to what's normal for a given negative format, such as for a Horizon Perfekt (aka Horizont) or Hasselblad Xpan, you may need to use condensers and lenses for a larger-format film.