A budget microscope for art examination

I have often been asked what kind of microscope is good for art examination. Briefly, you need a trinocular polarizing microscope with epillumination (from the top) and transmitted illumination (light from the bottom). I used to work in Brooklyn with the glorious  polarizing microscope Nikon OPTIPHOT 66. Moving back home in Italy I needed to buy an affordable microscope. I had no time to look for a used good microscope. So, I eventually turned to eBay and bought a budget microscope. It was so cheap and I was really thinking I were making a mistake, wasting my money, just getting a toy. This blog is about my positive surprise – I want share with you – for eventually getting a reasonable good microscope, good value for my money. Bottom line is that this kind of affordable microscope don’t make up for a quality one. I’m still on the look for another OPTIPHOT 66 but they can turn useful enough. This system I bought cost less than $1200 with all the needed accessories. A quality microscope even used with all the features said above would go for over $6000. so, i thought it was worth a try.

So, for $1200 I got a Polarizing  Microscope with Epi and Transmitted illumination (you need both, respectively for looking at cross-section and slide mounts). The Koehler illuminator for transmitted light feels really basic but it does its job  The rotating stage it’s not very easy to center – pretty rough movements – but after a while I managed to have it centered.  It has a set of objectives SEMI PLAN 4x, 10x, 40x. Eye pieces are both 10x and 15x so you get a total magnification which is enough for the kind of tests you do on pigments. It is all metal construction, though a bit rough overall. For polarizing microscopy it has a rotating analyzer for both epi and transmitted light, and Gypsum & Mica Plates.It makes it easy to get pictures with its trinocular Camera Port with 100% Light transfer and the 3 Mega Pixel USB Camera. Camera comes with its software but I prefer to use MICAM for all my imaging devices. For $1200 this microscope really comes with everything you need for art examination!

Well, let’s see some pictures! First it’s necessary to calibrate the system with a Stage Micrometer Calibration Slide.

 

Budget microscope. Transmitted illumination, stage micrometer calibration slide, objective 40X.

As a comparison, below is the same Stage Micrometer Calibration Slide seen with the  Nikon OPTIPHOT 66 using a 40X objective (Epillumination).

Not too bad, right?

Now, let’s see what we can tell on my collection of slide mounts of historical pigments. I did the same sequence of shots as in the movie below. The microscope used for this movie was the professional Nikon Optiphot 66.

 

Budget microscope. Ultramarine Natural, mount slide, Cargille meltmount. 40X. This budget microscope seems to deliver a pretty defined images of natural ultramarine crystals as big as 40 microns.

 

Budget microscope. Ultramarine synthetic, mount slide, Cargille meltmount. 40X. This budget microscope seems to deliver a pretty defined images of small (few microns) synthetic ultramarine crystals.

Pleochroism is well observed. The only issue is for the Becke line. Indeed for the observation of this subtle feature the quality microscope is necessary. Below a video showing some example with this budget microscope.

 

Regarding textile examination I show below an image of a wool fiber coming from my sweater.

 

Budget microscope. Wool fiber, 40x. Scales typical of wool are clearly defined.

And a fiber from the canvas of the painting I already blogged about in documentation #2.

 

Budget microscope. Cotton fiber, 40x. The typical twisted shape of cotton fiber is observed.

In conclusion, I would give this budget microscope a 6+ (C+ for US students).

Let’s improve your budget microscope
You can make this budget microscope from 6+ (C+) to 7 (B) with another $200. First you need to buy a X/Y microscope Mechanical Stage. The system is lacking it as do all other budget microscope. Though, you really need it for cross-sections examination. They go for $30 on eBay. These budget X/Y stages don’t provide a really smooth movement but for sure much better than doing without it at all.

 

X/Y microscope mechanical stage. You can fit one of these budget mechanical stage on any microscope that comes without it (they just have two slide holders).

Another improvement is a good set of objectives, such as 10X, 20X and 40X. They  go for $50 each.

 

Buy a good set of objectives.  The 20x objective is my favorite for photographing cross-section. It often gives you the right field of view for a painting’s sample.

 Optiphot 66 vs Budget Microscope

Let’s see now how the budget microscope compares to its professional counterpart on cross-sections microscopy.

 

Cross-section sample (10X objective) as seen by budget microscope (left) and Nikon Optiphot 66.

 

Cross-section sample (10X objective) as seen by budget microscope (left) and Nikon Optiphot 66.

 

Cross-section sample (20X objective) as seen by budget microscope (left) and Nikon Optiphot 66.

I definitely feel to suggest to buy a budget microscope when money is an issue. This is pretty good for teaching art examination. with just $1200 you get all you need to explore all the features of polarizing microscopy and cross-section documentation.