Cheapskate....

[Dave Humphries]

Hi Shirley,

So you don't think I need anything more than 2 fluorescent straight bulbs in their regular casing? No cloth over them?

I could imagine that with a thickly applied shiny oil paint might show a reflection of the tube nearest it. In that case the cloth may help, but I speak from theory, not experience.

Should I remove their plastic covers?

Yes

And do you think I need one on either side as long as it doesn't hit the lens? How about top lit.

Yes, 2 are needed for a more even spread of light, the illumination diminishes rapidly with increasing distance, so don't have them too close, hence the suggestion of 45 degrees to the picture.

Here's the idea, but you'd turn it on its side so the painting and lamps are vertical I guess (and larger of course). Note the shades to prevent the light hitting the lens (mounted on column).

If you try to get away with one (at top), you'll have a gradient of illumination that would need fixing in post processing (PP). You may not see it by eye, but it will be obvious in a shot.

Although if far enough away that distance to top edge and distance bottom edge is almost equal, it won't be too bad (but will be quite dim), I think this is impractical, hence two lamps needed.

I think I am right in saying that if the lamp to one edge and lamp to the other edge varies by more than 1:1.4 (as a ratio), there will be a stop difference in exposure - someone please correct me if my "head maths" is wonky.

Do I need to be sure there is no other light hitting the subject? Like outside light or ceiling lights?

Inside lights, especially if tungsten, yes and also especially if they are bright and/or close to the picture.
If you view the LCD of the picture illuminated and get the histogram on view and cannot see the difference switching the inside room lights off and on, then it should be OK, it's all a matter of proportion.

Cheers,

[Scout]

Dave, that is great, thanks! I can't wait to try it this way. This styrofoam is out of here!

Another question... should I be using a polarizer on the camera? Probably won't matter I guess.

Will a polarizing lens let me photograph paintings that are already under glass? Or do I need to unframe them?

I hope you don't get tired of these questions.

[Dave Humphries]

Dave, that is great, thanks! I can't wait to try it this way. This styrofoam is out of here!

Another question... should I be using a polarizer on the camera? Probably won't matter I guess.

Will a polarizing lens let me photograph paintings that are already under glass? Or do I need to unframe them?

I hope you don't get tired of these questions.

Hi Shirley,

Good.

Here's the tutorial, scroll down to the small picture on left of net/lace curtains and a window and hover mouse on and off it to see the difference it makes. That is the maximum you'll get because the light from the curtain hits the glass, bounces off and enters the lens in parallel with the light from the wall outside the window, putting the polariser in almost removes the curtain light leaving the view out better.

However, the polarising filter will only help with reflections at certain angles and with the angles of the lights and camera we're suggesting, I don't believe it'll help.

Obviously better without glass, but if clean both sides, it may not be so important. Obviously you don't want to risk damaging the artwork though.

Cheers,

[Inkanyezi]

It depends a bit on how big paintings are, what distance you need to put the lights from the artwork. But I'm sure you'll figure that out; the 45 degrees setup is pretty standard, and you should not set them so close that lighting becomes uneven or you see reflections.

There's a consideration regarding modulation of light, depending on what kind of ballast is used for the FL tubes. With a magnetic ballast, the light will flicker at a rate of 120 Hz, so you need an exposure that is substantially longer than a full cycle of the AC power. I think 1/30 s or longer is quite OK. There are electronic ballasts that do not modulate the light, but only the higher quality ones with a large smoothing capacitor. The univolt ballasts usually modulate almost as much as a magnetic ballast. The depth of modulation is about 30%, and it will be clearly visible as banding if you shoot with a too fast shutter speed.

Once you set it up it is not difficult, and if you use 954 colour you won't need to cut off daylight that enters the room. Incandescent light sources however should not be so close that you notice them.

[rpcrowe]

Hi Shirley, err Scout...

I suggest that you shoot in RAW and include a white or gray target in your first shot. That way, you can pretty well balance the color temperature of the lightsource.

I have shot a lot of artwork and have most often used bare 3200K (either tungsten or halogen) bulbs in reflectors. I sometimes used a polarizing filter (over my light source) this can reduce the amount of reflection on your artwork. I have had the most problems with reflections when shooting oil paintings because the heavy brush strokes sometimes reflect light from any angle. However, the large polarizing filter material needed to cover a light source is expensive and difficult with which to work...

Needless to say, when shooting, your photo lights should be the only light in the room. This is to prevent reflections from the ambient light sources. This is not possible in a museum and could be a problem in an art gallery unless you have after hours access.

Another possible way to light artwork is to use natural light outside. I don't recommend harsh sunlight but, a diffused shady location would work. Always remember to shoot the balance card with each group of images,

[Scout]

Thanks Inka, got it! I'll be experimenting with those. Very helpful.

Richard, I don't do oils. I paint in Watercolor like the truck above. So it's most always a mat finish. I have photographed in the out of light area outside and that was OK but I photograph my paintings as I paint them so I can make tutorials and maybe a book in the future. So it is very inconvenient to take it outside. I am currently using two 3200k tungston bulbs behind a white cloth (a bed sheet actually) I know you guys are getting a hoot out of this.

I have never used a white or gray card. Do I have to buy a special card? Is it placed on the painting or just in the frame beside the painting. Can you tell me kind of how it is used and why? I always shoot in RAW. I edit in PSCS4.
Thanks!

[ScoutR]

Hi Shadowman, yes, it's from To Kill a Mockingbird. I grew up in a town just like that one and looked just like her. I also followed my older brother around just like she did, I have the scars to prove it. I also use this name because I never liked my real name.

Is there another Scout on here?

Hi Shirley, very interesting what you are doing. Hope you take heed to the safety warnings though, it does sound a bit dangerous. We had a camera crew come into my workplace to take photos of some of the machines while they were running. Safety regulations do not allow the plexi glass machine hoods to be open while the machines are running so the crew set up their lights and cameras to film through the plexiglass. Within a few minutes we smelled something odd, and low and behold the lights were melting the plexi glass. Anyway, I digress, but those lights do get very hot.

Regarding the screen name, good to have another Scout here. I love "To Kill a Mockingbird" and next to Atticus (of course) Scout was my favourite character. My screen name is not based on Mockingbird though, I just feel like a Scout when I'm out taking photos. So no need to fret, I'm ScoutR you're Scout and we both picked out names for different reasons.
Welcome to the forum, I look forward to seeing more of your work. I don't think anyone else here is doing what you are up to.

Wendy

[Inkanyezi]

The grey card is a special card. Kodak grey cards have a grey and a white side, either should be "spectrum neutral", i.e. reflecting the same proportion of any wavelength. White paper (with whitening agent) won't do, it must be a special card. There are many different ones in the market, some of them with various colour patches and various density greys.

Either the grey or the white side can be used, and exposure of the grey card should be somewhere in the middle, so it's OK to just shoot the card in the actual lighting. Even the white turns out grey if the camera measures light from it. The grey side of the card can be used for evaluating exposure.

You put the card just where the painting is and make a first shot, a calibration shot for colour, then you take the pictures you want. Remember that FL tubes need about five minutes before they are stable in colour and light output, so this shot shall not be taken before the tubes have reached working temperature. When you shoot RAW, it is then pretty straightforward. You profile your conversion with that first shot and use that profile for the rest of the series.

[Scout]

Hi Wendy! Nice to meet you. Do you have a website? I'd love to see your work. I threw out the styrofoam. I appreciate the concern.

Inka, that seems like an easier way to fix the entire series at once. I labor in PS trying to get things right. I use a Mac (10.7 Lion) and nothing is the same on the monitor of others. I calibrate with colormunki. Print on an Epson 4880 and an R2000.

I ordered a card.

I checked out some fluorescent lights but couldn't find the number you gave me on them. I need to go to Lowes I guess. I'll get back to you about that when I've looked around some. Is there a place online? Thanks again for your time.

[Inkanyezi]

I'm in Sweden and don't know a lot of what goes on on the other side of the pond, but I'd try http://www.sylvania.com/ and see if they have what you need, and maybe they can suggest a retailer.

[Scout]

Thanks Inka. I went there but their site didn't help much but I found OSRAM and got a lot of information. But also raised a few more questions.

One thing. Since my biggest sculpture is 48" tall and my biggest painting is 30", how long a fixture do I need?

Also I only could find a T12... no 10. Will the older T12 work?

It mentioned a turn off/ turn on time as being 10 to 15 minutes. What's the story there? You have all been so helpful. Thanks!

[Dave Humphries]

It mentioned a turn off/ turn on time as being 10 to 15 minutes. What's the story there?

Inka suggests switching on for 5 minutes (15-20W tubes) or 10 minutes (36 & 58W tubes) before you use the light for photography.

This is because, although it may look white to your eyes, to a camera, it isn't, it varies in colour during those first five or ten minutes. Once the (heat) temperature of the tube has stabilised, so will the (light's) colour temperature. Then it is safe to start by photographing the white/grey card (as a series reference shot) and then pictures (and sculptures) themselves.

I would suggest a 48" (4 foot) tube would be the right ones to go for, you certainly don't want it shorter than the long edge of the frame.

Cheers,

[Scout]

Hi Dave, no I got the part about the heat up time. I meant, once you turn it off, you can't turn it back on for 10 or 15 minutes. Sounds like I need to leave them on.

Hey, also, any ideas on a vertical mount?

[Dave Humphries]

Hi Dave, no I got the part about the heat up time. I meant, once you turn it off, you can't turn it back on for 10 or 15 minutes. Sounds like I need to leave them on.

Ah sorry Shirley; stick, wrong end of (me I mean)

I have heard it said it wastes more electricity to switch them off for short periods than leave them on for 10-15 minutes.

They might sell DIY/construction lamps with a stand?
e.g. this (in UK)

Cheers,

[Scout]

Dave, LOL! You sound like my Dad! Chuckle!

I think I have one of those stands. A halogen, that I hate. Good idea.

[Scout]

Oh, I looked at the stands on that site. Interesting. Although, what about deflecting the light from hitting the camera lens? I'm so tired of jerryrigging.

[Inkanyezi]

As I said, I know little of what is available in the USA regarding FL tubes; when I have been there I have seen very different ones from the ones we have here in Europe, for example cold cathode tubes, which are not sold here at all.

There is no extra waste of current from frequent switching, but some ballasts do not heat the cathodes properly if turned on too quickly after being turned off. When I am in a photo session with lamps, I leave them on between shots, and even if I make a cup of coffee or go to the computer to do some editing.

If cathodes of FL tubes are not heated properly at startup, their useful life gets shorter, as they will then lose emission material from the cathodes; this material sets off at the end of the tube as a dark shade, and when all emission material is lost, the tube no longer ignites. When properly heated and not switched too frequently, FL tubes have very long life, between 10000 and 20000 hours. They do degrade during that time, and may change somewhat in colour.

The tube while heating may pass through stages of different colour casts, usually not greenish. It is when the tube is overly hot it gets a green tinge. Powerful tubes heat more quickly than those of 15 to 20 watts. My 5 minutes relates to 36 and 58 W tubes, ten minutes might be even better, but you should not do your shooting before the light has stabilised in power and colour.

I guess that if you communicate the ideas to people at Sylvania/Osram, they will help you get decent stuff. I know that they have warm cathode lamps and good electronic ballasts with smooting so that light does not get modulated by the AC frequency. (Modulation is twice the AC mains frequency, and only the better electronic ballasts eliminate it completely.)

[Dave Humphries]

Thanks, I have corrected my mistake above