A poor man's gel holder for studio lights

My studio lights

I use a cross polarization setup to photograph my oil paintings. It involves hanging linear polarized film over two lights, and then having a linear polarized filter on the camera lens turned 90 degrees to the polarized film. This eliminates glare on the painting because shiny highlights from the studio lights remain polarized after reflecting off the painting, letting them be reduced by the filter on the lens. Whereas the light that is scattered off the painting in a more diffuse way, the light I'm interested in capturing, loses polarization when it reflects off the painting and can pass into the lens freely.

But that's not what this post is about (see the link for more detail on cross polarization). The problem I had was suspending the polarized film in front of my lights. 

Professional quality lights are stronger and can take holders for such things. Maybe someday I can afford those. For now I use cheap clip lights from the home improvement store, which are too flimsy and not shaped correctly for gel holders. I don't have enough hands to hold two gels and work a camera, so I need holders.  And while the lights don't get very hot as far as lights go, they get hot enough that I couldn't just tape the film directly to the lights. And polarized film needs to be as flat as possible to be effective anyway.

So that's the problem. At first I tried making barn doors and other contraptions out of cardboard, but I found that even cardboard was too heavy for the flimsy clip lights. Also it was hard to attach to the light.

Here is my new solution, which works much better:

First get a hanging file folder with metal hooks. You will also need a wire hanger, some wire cutters, and some tape. Note that the tape will be touching the metal of the light fixture. My light fixtures get hot enough that I worry about the film, but they don't get so hot that they will melt tape. If yours do, look into some heat resistant tape, clips, or something else. You'll see what I mean later. By the way, if you are looking for polarized film, I bought mine online from polarization.com.

Step 2: Harvest the metal hooks from the file folder and recycle the rest. We only need the hooks.

Step 3: Tape the hooks to your film. 

Step 4, cut the hook off of the wire hanger and discard, and bend the rest into something like this shape. Essentially a big "V" with two small hooks on each end.

Attach the wire hanger to the clip light as shown. It's important to pass the wire through the coil of the spring on the light, as this will support most of the weight. Tape is used just to stabilise the hooks on the top of the light. Here is where you may want to see how hot your fixture gets and adjust accordingly if you think it gets too hot for tape. Although that would be really hot. Also note the small hooks are facing up.

Hang the film from the wire hanger. The setup is complete. One thing I really like about this setup, besides the fact that it fulfills my goals, is that gravity tends to always keep the film hanging vertically, which is important for the cross polarized setup. I've used this setup now many times for photographing my art and it is vastly superior to holding things up by hand.

Good luck and if you have any questions feel free to reach out.

A simple artist inventory with Google Docs and Python

The goal, a basic spreadsheet with images in cells.

The goal, a basic spreadsheet with images in cells.

I'm terrible with organizing inventory, so I wanted an easy and simple solution to track my paintings. I also didn't want to spend any money. There are commercial artist inventory programs, like gyst, but that seemed like overkill for my needs. A spreadsheet, like what is available in google docs, seemed perfectly adequate.

I also keep all my images and documents online these days. There are privacy concerns, but after years of losing data and dealing with bad disks, zip drives, and burning CDs, for me it's worth the trade off. So using a web service like Google Docs/Drive made sense for me.

I already take photos of my artwork and store them on Google Drive, and so far I've just manually made a web sized version in Photoshop. But initial tests with this system and google docs showed two problems: 

  1. Once you have dozens of images in a spreadsheet it really bogs down, even at 'web resolution'. I really needed thumbnail images.
  2. Adding an image to a google sheet makes it just 'float' on top, rather than be in a cell. This is annoying.

To solve the first problem I needed to make dozens of thumbnails, which I didn't want to do by hand. This is a perfect task to automate. The short script I ended up making is located here.

I already have all my high res art photos in one directory on Google Drive. Running this script on that directory generates thumbnails and medium sized versions with the suffix "_tn" "_sm". So for a given image I may have:

  • chinatown01.jpg (my high res original, made manually).
  • chinatown01_det01.jpg (an optional detail image, made manually).
  • chinatown01_sm (a web sized image, made by script)
  • chinatown01_tn (a thumbnail, made by script).


That solves the thumbnail problem. Now, to use them in a spreadsheet. 

Here is my google spreadsheet template, feel free to save a copy.  You change the year to get automatic "inventory numbers" on your paintings, and can simply copy and paste a new row when you add a painting. 

Getting the images to be locked into a cell requires the image be hosted online, and the use of the '=IMAGE' formula in the spreadsheet. Fortunately when an image is on Google Drive with "link sharing" enabled that counts.

A Google Drive folder full of images and auto-generated thumbnails

A Google Drive folder full of images and auto-generated thumbnails

To add your image go to Google drive, right click on any of the thumbnail images, and select 'sharable link'. You will get a popup with a long URL. At the end of that URL is a string of letters and numbers, something like "0B08IThSJpP5tc2Z4UmtUjNxYm8". That is the image's "ID". Copy that part and ignore the rest.

Back in the spreadsheet you will see a line I've left in the image tab. It looks like:
=IMAGE("http://drive.google.com/uc?export=view&id=",3)

Paste the image ID after the '=' sign. It should look something like this:
=IMAGE("http://drive.google.com/uc?export=view&id=0B08IThSJpP5tc2Z4UmtUjNxYm8",3)

Your image should appear in the spreadsheet. This also works with any image online if you change the entire URL, not just Google Drive images. So if you use a different cloud storage solution, or you keep your images online, that works as well.

I've found this to be reasonably fast. I was able to add about forty paintings to the spreadsheet in about an hour. When I make a new painting I save it in my image folder, run my script, copy/paste a new row in the spreadsheet, change the image ID, and edit the details.