4-Blade Darkroom Easel System

Overview

This is my attempt at designing a relatively inexpensive and easy to assemble 4-blade darkroom easel using primarily off-the-shelf parts for the frame and 3d printed components for the blade sliding and locking mechanism. Materials cost is in the ballpark of $50-$100 USD, ultimately depending on what you already have available. As designed, it supports a max paper size of 8x10in, but with longer aluminum extrusion and rulers, you should be able to support larger paper.

Materials

Frame

- 4x - 300mm 2020 aluminum extrusion

- Left and right frame edges

- 6x - 400mm 2020 aluminum extrusion

- Top and bottom frame edges and bottom half crossbars

- 12-16x - 2020 corner brackets

- These hold the frame together and are the primary source of stability

- Printing these is viable but the frame will have significantly more flex

- 2x - 2020 hinges

- Printing these might be viable but I never tried. Metal hinges make it much more sturdy

- Varying amounts - 2020 slide-in/drop-in T-nuts + matching bolts

- Everything can be done with slide-in T-nuts but not everything can be done with drop-ins. An assorted is best

- You'll probably want various length bolts

Sliding Components

- 2x - 12in thin metal ruler

- For the vertical blades

- Look for one that has slightly longer ends. Mine is closer to 12.3in

- Harbor Freight sells the rulers for ~$2 each but they come with a cork bottom that needs removing.

- 2x - 16in thin metal ruler

- For the horizontal blades

- If you can't find a good one you can also cut a longer ruler to size

- 8x - M3 bolts (12-16mm)

- Used to align/lock rulers/blades in place

- 8x - M3 nuts

- Same as the bolts

- 4x - M5 bolt (12-15mm)

- Used to secure the locking knobs to the sliding blade mounts

Paper Base

This has the most flexibility. You can use any material of any size as long as 1) it's no more than 0.75in thick, 2) it fits within the 300x400mm frame area (accounting for the corner brackets as well), and 3) it's stiff enough to keep the photo paper flat.

Here are a few options that I think work well for this, starting with what I used:

- Melamine MDF board - 12x10x0.75in (LxWxH)

- Acrylic sheet

- A perfectly sized, very flat book

Printing

Modifications

You don't have the exact same materials as me, so it's likely you'll need to make slight modifications to some of the models to fit your needs. I'll try to outline most of the possible changes necessary here:

- ruler lead slider