As you may have read somewhere else, my beloved is a painter (she’ll deny it, but it’s true). She works with oil on canvas, and has recently also picked up aquarels.
My task is to photograph her pictures as accurately as possible, for her portfolio web site.
Mind you: this is not a howto! What you’re reading is MY way of doing things. I’m not saying you need to copy this, but if you struggle to get it right, maybe there are some ideas in here that help you get on the right track.
The Struggle — to get the colours as true as possible
Yeah, let’s start there. That was the biggest headache.
The important bit is to get your light as controlled as possible, so you will need a light source that gives reproducible results. I know for a fact that not all flashes will do that — I had a flash of questionable quality of which the colour temperature would bounce up or down as much as 300K, so between 5200K and 5800K.
Reputable flashes usually wouldn’t do that. I’ve had a Nikon flash that was as close to 5500K as I could judge, and I have two Minolta 5600 HS-D flashes that are dead-on as well.
My current studio setup uses two Godox units, which theoretically may be a very little bit off (it’s too close to call), but it’s a negligible amount, and it’s exactly the same every shot.
If you want to check your flash unit, put up a sheet of perfectly white paper, photograph that, and then let Lightroom or Bridge sort out the colour temperature by “pointing” at the paper with the White Balance Selector, so the software knows that’s supposed to be white. Don’t worry about a few numbers off, rounding to the nearest 50 should be fine.
And yet, I had trouble getting the colours exactly right — with a bunch of Sonys, an S2 Pro, a Canon of which I forgot the designation, and the Nikon D3 was cooler than any of the others.
The ONLY camera with which I could get an end result that even my wife approved of was the now 17 year old Sony A900. This is not entirely unexpected — the only Minolta digital SLR, the Dynax 7D, had an excellent reputation when it come to accurate colour reproduction, and the Sony Ax00 cameras were essentially Minolta products (they even have the on/off switch where I want it).
The difference is: the colour red is much harder to photograph than any of the others, because it appears darker than it really is.
Where even the A99-II clips in the red channel and starts to lose detail, the A900 somehow ekes the most detail out, and the overall colour balance of the A900 is noticeably better.
Wait. Did you say “noticeably”?
Yes. But ONLY when you compare the photo on a calibrated screen with the original painting under a daylight (5500K) light source. And that’s about the most critical comparison you’ll ever get to work with. In normal photography, you’re never going to notice.
And if your wife isn’t a stickler when it comes to colours, you might be able to get away with more than I can.
I now know that, if I shoot at the camera’s white balance set to daylight, and in Lightroom, I drag down the saturation a bit, I can get the colours as close as makes no difference.
So, if you have multiple cameras at your disposal, it pays to see which one serves you best.
My camera and painting setup
This is not the hardest part, but it requires some precision!
I usually use an 85mm lens or a 100mm lens. This allows me to take some distance even if the painting isn’t too large, and keeping some distance will help you to prevent unwanted distortion.
I set up the painting on an easel. This means it will be leaning slightly back, or it will topple over. Which will get you in trouble with the artist or owner.
Since you want the line of sight through the lens to be at a 90 degree angle on the middle of the painting, this means that you will have the camera slightly higher, and tilted forward a bit, so that it looks straight at the middle of your artwork.
You don’t need to use rulers and angle measurements for this — you can just line up the camera by looking at the painting in the viewfinder. If the top of the painting looks just as wide as the bottom, you’re good. If the top looks narrower, you need to raise your camera; if the top looks wider, your camera is too high. Same thing is true for right and left — use the pics below as a reference.
I know you can adjust this in Lightroom as well, but you’ll want to keep these adjustments to a minimum. So, endeavour to get it as good as you can get in your viewfinder.
This is also a good time to check the camera settings. The choices you make depend on your workflow and equipment. The Sony A900 assumes that flash has a 6000K temperature, but I’m not worrying too much about it — I know that my Godox flashes output light very close to 5500K, and that is what Lightroom assumes when I choose Flash as the colour temperature.
I set the camera to manual exposure, 1/125 with f5.6. This is because I use pretty good lenses, of which I have verified that, at f5.6, their performance is close to optimal. If you’re using a kit lens, you may want to use f8 or thereabouts to get optimal sharpness.
Using my Godox system, I leave determining the exposure to TTL. If you don’t have a good TTL flash metering system, you’ll have to use a flash meter (expen$ive!), or make a lot of test shots to figure out what works best. The good news is that, if your camera, your flash system and the distance betwee flash and artwork is consistent, your results will also be close enough, so you can figure it out once, write it down, and then rely on that for the next 20 paintings.
Note: if there is a lot of stray light leaking into your studio, you will want to crank up flash power. If you’re using TTL, simply selecting a smaller lens opening will do. If you are using manual, you’ll have to sort that out yourself — close down the lens opening with as many stops as you increased the flash output.
Warning: if you are going to rely on TTL, very light paintings and very dark paintings are going to screw you (up to 1.5 stop), but for most paintings, you stay well within the acceptable margins of a Lightroom correction.
Light setup – how to avoid unwanted reflections
When you’re photographing aquarels, you can get away with evenly spread direct light, but when it comes to acrylic or oil on canvas, you have to spread out your light as evenly as possible, or you will get unwanted reflections — especially if the painting is varnished! After a lot of experimenting (peppered by an array of Dutch choice expletives), I settled on two flashes on stands with flash-through umbrellas (the softest light source I have at hand). I aim them at the ceiling, which is pretty neutral, and raise them to 10-15 cm from the ceiling, in order to prevent any direct light hitting the painting.
The light stands are about 1.5m away from the painting.
When that’s all set up, I wait for the sun to disappear and close all the sunscreens. I focus, then I make sure the camera is on manual focus, and I verify that both flashes are on standby. ISO 100, manual exposure, 1/125s, f5.6? Good. Then I turn the lights off, making sure the computer monitors are off too, and I pull the trigger on my remote.
Just once is enough if my setup is correct.
Processing the photo
The only thing I need to do is to crop te image to the desired format — I crop it so that the painting fits in exactly. Then, I set the white balance to flash, I drag the saturation slider back -30, and then compare what’s on screen to the actual picture to see if the exposure is right (I’ll let myself go half a stop up or down in Lightroom). In my workflow, this nails it every time.
If you’re still struggling to get it right, feel free to pop me a line — I might be able to help you out!