Making A Camera Lucida Drawing Tool

Video | Posted on by spapasavva

Camera Lucida Drawing Tool (FREE DOWNLOAD) | Savvas Papasavva (miscpro.com)

In this video I will share version 1, 2 and 3 of a 3D printable camera lucida that I designed in CAD modelling software. I’ll go through the designing process over these iterations, share some 3D printing tips, and the subsequent assembly procedures. There are chapters available in the timeline if you prefer to skip to a specific section.

If you don’t know what a camera lucida is, it is simply a tool to aid drawings from life. It works similarly to an autocue or teleprompter in that a reflected image is displayed on a transparent surface which can be aligned, in this case over a piece of paper, to help plot the composition of images, drawings and paintings. The artist when using the tool, sees a superimposition of both the subject which is ahead, and surface being worked upon below. There are some great videos, discussions, and demonstrations of modern recreations of these old tools, that you can see onscreen and which I’ll link too, somewhere.

There is also a wonderful book published in 2001, and television documentary from 2002, by David Hockney in collaboration with Charles Falco, called Secret Knowledge: Rediscovering the lost techniques of the Old Masters. The title is quite suggestive, but in essence, the artworks that we so often hold on a pedestal, and judge other artistic endeavours by, or even just put ourselves off attempting to make art because of perceived raw talent and genius needed, were in fact heavily reliant on optics and mirrors, and bits of string, and a little bit of maths, to help compose images with a photographic likeness.

Various bit of equipment which predates chemical photography, and were a stepping stone towards that invention, were being used by artist, scientists and intellectuals working in Florence and the Flanders from the 15th century onwards.

There are a few types of camera Lucida’s that I have seen, one type using a glass prism and a simpler version, a piece of mirror and clear glass, which is what I’ll be recreating. And there is a 3D printed version available, designed by Chris Borge, but I had to make one myself. Because through making I think I’ll understand the tool, and process to use it more thoroughly.

VERSION 1

Version one comprises of a central body piece with groves, openings, and threaded mounting holes, two side pieces which have indentation for mirrored and clear acrylic pieces as well as corresponding through holes for mounting, the aforementioned mirrored and clear pieces of acrylic, eight M3x10mm machine screws and four M3 locking nuts, the top viewfinder piece, and a second-hand eye cup that I bought from Ebay, because I thought it looked interesting.

I am using acrylic mirror and clear acrylic pieces, and not front surface mirror, or partially silvered two-way mirrored glass which supposedly works better when using the is contraption in bright outdoor conditions.  I’ll decide whether to replace these later depending on how successful these are. And this is a short animation of the parts, pause the video if necessary. And following that I’ll share the version one assembly process.

Now there were some issues with version 1 which prompted me to develop the design, and these included the viewfinder, which while looking retro and cool in fact had a restricted viewing angle. Which you can see better form this photo down the viewfinder. Also, I couldn’t find a suitable dioptre lens to correct for use without my glasses. That’s the corresponding sketch where I wasn’t wearing glasses.

The 3D modelled screw threads were not located in the best place and one actually cracked.

The protrusion for the smartphone clamp needed to be redesigned as well, the tapper angled increased and round-over added to the end corners. This was needed to increase the grip of the universal Manfrotto phone clamp that I was using.

VERSION 2

For version 2, I redesigned the viewfinder so I could use it while wearing glasses – coz I just have to use them now. Getting old and all that. I made some changes to the main body, included adding a couple more threaded fixing positions as well as adjusting the threaded mounting locations so there was a little bit more space around the opening, which should help with splitting.

Reinforcing the 3D model threads of the M3x10mm machine screws and that has a subsequent knock-on effect because the side pieces are slightly different. Overall, it’s slightly different design which should be more robust and easier to use.

I also changed the shape of the tapered grip at the rear of the main body, by increasing the taper angle, and chamfering the top and bottom edges, which helped to increases the clamps grip.

I had designed a slot at the bottom of the piece for a size A Cokin neutral density filter, which is sometimes needed for outdoor conditions, and may help by making the image clearer. But I’m still waiting for that to arrive in the post before I can measure it with me vernier-calliper and adjust the size in the 3D model. I could also use the slot for any additional attachments, like a photo or small object holder. But that is something for the future version.

VERSION 3

I realised I wanted to send a few of these to some artist friends of mine, for them to use and potentially feed back to me their thoughts, and I realised the shape would increase the cost of shipping. So, I redesigned the object again, this time so the main body was split into two sections, one of which rested into a new slot recess.

I also finalised the 3D printing process. Here I reinforced the threaded mounting holes by adding modifier shapes in the form of cylinders, which I specified the size and location. They are just a little larger than the threaded openings, and I could choose to modify the infill density and pattern, so they were higher at 90% compared to the rest of the model which was 20% infill. The additional material around the hole should further help with the splitting issue I had earlier during version 1. I also did the same around the through holes, on the side pieces, which meant there was more material around the opening to help with compression of the plastic by the machine screw heads. And which while filming I noticed I made a mistake, and only positioned one half appropriately, so I corrected this.

I wasn’t sure about printing these parallel to the printer bed, as I think the thread quality and detail is better the other way around but needs must, so I printed them this way and after using them it seemed to work ok. 3D modelled threads are not designed for repetitive use – and once something using them is assembled, you most likely are not planning to disassemble it.

And here is another animation of the parts which makes up version 3, with captions, and which you can pause to read if necessary.

This is version 3 which I designed to be flatpack, and be a little bit easier to post as I’d like to send a couple of these out to friends to try out.

The second you hit a little bit of resistance, you just stop. You don’t want to thread these too tight as you are only going into 3d printed modelled threads. And they will loose there form, the pitch very easily, it won’t take much to damage these. So once that gap closes, every so slightly you feel a bit of resistance, you stop there. And that’s good enough. Because it overlapped no light will get in. This new piece (eye cup) is a little bit different too, I’ve taken off the edges here so there is less chance of jabbing yourself in the face.

After saying all that, I received some new acrylic pieces which were a little bigger than what I had ordered, and while assembling a second kit, two 3D pieces became wedged apart when slotting in the acrylic, and the mounting holes I was worried about lost their threads becoming unable to tighten. I felt that it was kind of my fault, as when you get stuff cut, there’s aways a working tolerance, + or – a few mm, and I hadn’t specify that I needed them quite accurate, or just shy off.

I approached the supplier:

“I’m not asking for a refund but if I re-order I need to know if this can be made exactly as specified as the parts need to fit into custom made slots – which I only factored 1mm tolerance. Do you have access to a laser cutter for cutting plastic by any chance? Please advise, and best wishes.”

And they replied:

“Kind sir, sorry about that, when you are ready to re-order, we will lasercut at the same cost and send a couple of spares. Kind Regards”

But this made me think – well I’ve got two sets of acrylic pieces that are now defuncted, unless I design version 4, which really should be a parametric version.

VERSION 4

This is version 4 – the parametric version, which I didn’t plan to make but I should have.

Parametric models, contain key parameters such as the height and width of the acrylic pieces in my case, as references which would allow me to interactively make changes to the design, by simply changing a dimension which can automatically update the 3D model. It is a great way of making efficient and easily adjustable designs, and in this case reduce waste.

It is cobbled together – which worked when making the minor variations based on the measured dimensions of the acrylic pieces, but it is not perfect. Designing like this can take days tbh, because of the knock-on effect changing one measurement has on another part of the design, and the amount of testing that must be done. For example, I can’t change the width of the mirrored pieces and make it as big as a house, as you can see the model breaks. But eventually I achieved something that more or less worked.

While I was at it, I took this opportunity to make some change including simplifying the side pieces, so the recess and slots were at the same depth.  This seemed essential for converting to a parametric design as it simplified the mathematical relationship between the parts. I also adjusted the design of the main body top piece, so that could be printed vertically in the same way as the main body rear piece, thus improve the mounting thread resolution. And while I was at it, I made a viewfinder cap. It occurred to me that if dust got inside, cleaning would be an issue. It may be tempting to dismantling the model to access the interior, and I should really reduce or avoid that, to prolong the life expectancy of the 3d modelled threads.

DEMONSTRATION

I’m now setting up the camera lucida to draw with. Starting with the arm which will hold the drawing tool clamped to a table. I am using a Manfrotto magic arm, but you can also use cheaper lighting clamp stands such as the one on screen – but the magic arm is much easier to use and fix into position. I locate the arm so the camera lucida overlook where I will place a piece of paper and points towards my subject which in this case is a romantic wax peanut candle. I attach the phone clamp and tripod plate to the camera lucida, and then clip that assembly to the arm.

I also use a beautifying ring light to illuminate the subject, which is important because the strong contrasting light will make the object visible in the viewfinder. Of course, I should also make sure I am comfortable looking through the device and while drawing so I don’t do my back in.

I can then draw marks on the paper to outline the subject within the field of vision available to me – and with a fair bit of accuracy capture the object but also its environment. When correctly done the foreshortening of the room or objects, creating a sense of realistic perspective. Once those are documented, I can ignore the camera lucida and draw what I see, making marks to populate the page with the subject.

This drawing probably didn’t come out as well as it could but later that evening, when the light levels had dropped, I drew some toys. Those conditions help me see the subjects clearer in the reflection. And I didn’t have to wave my waving my hand under the lucida to create shadow with which to see detail. These drawings of toys sitting on mugs, seem much more expressive and free flowing, and they don’t automatically shout out – I’ve been traced, he’s cheating, all lies.

I also tried replacing the mirror and clear acrylic with a front surface mirror and a two way see-through mirror, which actually further improved the image quality, and removed the double image created previous setup. That said I could see less of the paper, so I’m not suer which is actually more helpful. Anyway I think this video has come to a natural end. I hope you enjoyed peering into the process of I designed my own camera lucida. I’ll link to all the interesting sources which helped me make this video on my website, and if you would like to make one yourself, the design will be available to download. I’ll write some directions in the comments or description. Thanks again for watching and don’t forget to sacrifice a thumb to the algorithm gods. A catchphrase which is losing meaning in each video, as I’m using fewer dangerous handtools with which to sacrifice my own thumbs.