Artificial lighting

[Mike Dodson]

I just received catalogs from Jerry's Artarama and Art Supply Warehouse. They are now carrying the Lumichrome fluorescents.

[ReNae Stueve]

Originally Posted by Marvin Mattelson

This is in response to Michelle's report of

Natural light has a Color Rendering Index (CRI) of 100. CRI refers to how well the light from the bulb reflects true colors. An incandescent bulb has a CRI of approximately 50. The lights I use in my studio have a CRI of 98. They are fluorescent tubes made by Lumichrome.

Marvin, I'm very sorry, but your information on light sources and the CRI index is incorrect. First the CRI of incandescent lamps at 2800K is 100. It is used as the basis for all comaprison to warm lamp sources. However, CRI is only an index used to compare light sources of similar Kelvin Temperature. The CCT or Kelvin rating is a rating achieved by heating metal to a Kelvin temperature that mimics the color of the lamp 2700K being standard 130v incadecent lamp perceived as a yellow/white or warm white. mid day sun light at 6000K significantly bluer/cool white and is the basis for the "daylight" flurescent lamps you refer to. Late afternoon and morning are a different story. At these tmes daylight is much warmer.

Again, the CRI of incandecent is 100, fade to 97 as the lamp "burns in" The necessity for a CRI comparison is due the the various mix of phosphors used in flourescent lighting. Originally developed to save energy and increase lumens/watt ratio the early flourescents were horible CRI performers. BUT view your 8 color chart under incandescent 100 watt unfrosted lamp at 100 CRI and then a Chroma75 falling at 7500K CRI 90 and you will see what I mean. Colors ae percieved as completely different.

There is no such thing as the "true" color" of any material; the perceived color is a function of the light under which the material is viewed.

If you want to render a painting that creates a feel of late day/or evening by the fire, use incandesent. If your painting is to model mid day sun use the flourescents with 6000K BUT be an informed consumer, The self-ballested lamps you're buying from art magazines for $30.00 each are the same lamp made by the same offshore factory as the one labeled for Phillips and GE and Sylvania sold at Graybar or Hughes or Graineger for $8.50

Select the temperature you are striving for and THEN select a high CRI in that temperature. And remember that your painting will be viewed under an incandescent source most likely a halogen at 3500K to be at full oad or dimmed to 2700K in most instances.

[Allan Rahbek]

There is no such thing as the "true color" of any material; the perceived color is a function of the light under which the material is viewed.

Hi ReNae,

You keep it so "surprisingly" simple. KISS.

I too believe there is no "true" color. Being a trained decorator painter (house painter) I

[ReNae Stueve]

Originally Posted by Allan Rahbek

But if you actually paint the colors you see, I believe that the result should not be so bad after all.

As Marvin Mattelson advocate it is important to get the right light values. And that is one thing you CAN do in a dim light.

Allan

Allan, absolutely!!!!

The question that you have to answer when forming your composition, what color DO you want us see?. What is the mood and feel you're shooting for. Then select the light sources that will facilitate your choice and paint what you see. You are the creator. The key for me is to have ENOUGH full spectrum light = foot candles, at the task to see what I'm doing. And yes it should/must be the same temp. as what is lighting your subject. Consistency. That's why artists used North light before electricity, because it was more consistent throughout the day.

Color perception is subjective. But the technology behind various light sources is not. The above mentioned CRI reference was applied incorrectly to the subject and being that my day job is a commercial lighting and electrical designer/distributor I thought I'd throw some light on the subject. . CRI is a grade. Think of a 4th grade student who gets a 98% on his science test. Is he a better scientist than my 5th year bio/chem daughter who got a 92% in molecular what ever? Not really related. Doesn't mean the kid's not smart, but it's relative to the class.

I assumed that Marvin, like so many others had been misinformed by a lighting manufacturer who wanted him to buy their expensive lamps. Think about this. If fluorescent light was a good full spectrum light source, why do cosmetic counters, art museums and studio stage designers use halogen? I'm not saying the light Marvin mentions is bad. It's not, but bang for your buck, a Solux 5000K MR16, selling for $8.00 can be placed nicely in a track lighting set up, manipulated with gels, filters and barn doors, to get anything you need. It's dimmable and low harmonic with the right x-former.

I've used fluorescent in the past at home, when I first started painting, but as I woke up and started applying the knowledge from my day job to the problem of task and set-up I realized that the power bill was the least of my worries, when trying to paint at night. Hit the Solux web site for all of the technical blah blah if your head is not swimming enough yet.

[Marvin Mattelson]

Marvin, I'm very sorry but your information on light sources and the CRI index is incorrect.

RaNae, with all due respect for your professional acumen, there are many sources of information that refute your contention concerning that the CRI of incandescent bulbs is 100. I don't make up numbers or information. Many "experts" in any number of fields disagree with each other. It may be your opinion that I am incorrect. You offer far from conclusive evidence to satisfy me.

You quoted the soltex website. They have an agenda of proving their lights are superior to fluorescents and so they have listed data that serves their end. In the printing industry where color is extremely critical, color corrected bulbs are utilized. If you've tried the soltex bulbs, you would know that they are expensive, due to the cost of the fixtures. They are harsh and not soft. They generate far more heat than fluorescents.

In my experience most museums and galleries light their paintings poorly. They use warm bulbs to try to punch up the color. It is virtually impossible to see real color nuances. In the American Wing at the Met there is a gallery where the paintings are lit by skylight and augmented by halogens. Again in my opinion the color during mid day is far superior to the paintings in the museum's other galleries.

In terms of your contention that the CRI of incandescent bulbs is 100 I would site the CRI listings on the following link: http://www.gaiam.com/retail/gai_cont...article_id=583
I don't see 100 CRI listed anywhere. Are they also incorrect?

What about this page: http://www.survivalunlimited.com/litebulbs.htm These people are also lighting professionals aren't they? At the bottom of this page is box containing the following statement: Standard incandescent bulbs have a 40 CRI.

Personally I don't really care about scientific hairsplitting. I go for what works for me.

The bottom line for me is color perception as it relates to painting portraits. In the case of incandescent lights, it is very difficult for me to perceive subtlety in skin tones. All colors look out of whack. In terms of my being able to differentiate color nuances, when compared to incandescents my Lumichrome bulbs are like the difference between light and day.

[ReNae Stueve]

Originally Posted by Marvin Mattelson

RaNae, with all due respect for your professional acumen, there are many sources of information that refute your contention concerning that the CRI of incandescent bulbs is 100. I don't make up numbers or information. Many "experts" in any number of fields disagree with each other. It may be your opinion that I am incorrect. You offer far from conclusive evidence to satisfy me.

You quoted the soltex website. They have an agenda of proving their lights are superior to fluorescents and so they have listed data that serves their end. In the printing industry where color is extremely critical, color corrected bulbs are utilized. If you've tried the soltex bulbs, you would know that they are expensive, due to the cost of the fixtures. They are harsh and not soft. They generate far more heat than fluorescents.

In my experience most museums and galleries light their paintings poorly. They use warm bulbs to try to punch up the color. It is virtually impossible to see real color nuances. In the American Wing at the Met there is a gallery where the paintings are lit by skylight and augmented by halogens. Again in my opinion the color during mid day is far superior to the paintings in the museum's other galleries.

In terms of your contention that the CRI of incandescent bulbs is 100 I would site the CRI listings on the following link: http://www.gaiam.com/retail/gai_cont...article_id=583
I don't see 100 CRI listed anywhere. Are they also incorrect?

What about this page: http://www.survivalunlimited.com/lite bulbs.htm These people are also lighting professionals aren't they? At the bottom of this page is box containing the following statement: Standard incandescent bulbs have a 40 CRI.

Personally I don't really care about scientific hairsplitting. I go for what works for me.

The bottom line for me is color perception as it relates to painting portraits. In the case of incandescent lights, it is very difficult for me to perceive subtlety in skin tones. All colors look out of whack. In terms of my being able to differentiate color nuances, when compared to incandescents my Lumichrome bulbs are like the difference between light and day.

Marvin,

Incandescent is the BASE LINE for CRI comparison in the warm range of 2700-3400K in the industry. The reason it is not listed in most literature is due to the fact that CRI relates to gas filled phosphorous light sources. Regardless of what you have read, in promotional literature, it is clear that you don't understand the science behind lighting, and the manufacturing process. If you like the fluorescents, have a ball. I prefer Halogen. Referring to the light s "yours" and defending its sales claims, as your own, to me seems quite odd.

I really don't know what to say, so I won't say anything more.

[Marvin Mattelson]

I prefer Halogen. Referring to the light as "yours" and defending it's sales claims, as your own, to me seems quite odd.

You're absolutely right I don't understand the "science" behind lighting. I wasn't defending any sales claims as my own. I was pointing out that there seems to be a lot of conflicting facts on the subject. I do, however, understand the practical application of lighting as it relates to my paintings and my studio situation.

I pride myself in the knowledge I've cultivated regarding the painting process. I'd like to humor myself and think that some others out there may agree. I'm well aware that there are those would strongly debate that fact. I consider myself an idiot savant regarding portraiture and although I may be clueless regarding life in general, when it comes to painting I am very discerning and not capricious with my choices.

Just because a so called expert may express certain "agreed upon" theoretical tenants, I accept nothing until I prove to myself that there is validity there for me. With painting, for example, I'm often eschewing popular notions because I want the best solution possible. I often find the answers doing the exact opposite. My students are proving over and over that my theories bear themselves out. If a problem arises I reevaluate and dogmatically search for a better answer or a better explanation.

Science is based on experimentation and testing. That is exactly how I have approached the choices I've made regarding my studio lighting. I have painted under every type of color corrected bulb throughout my career. When I tried halogen bulbs I found the light to be very harsh with hot spots, casting sharp shadows from my hand and brush onto the painting surface . The halogens also generated a lot of heat. The lower wattage and softer quality of the Lumichrome bulbs give off far less heat and illuminate the painting on my canvas with an even and diffused light. I've always searched for the possible best solution and I've never been satisfied. That is until I found the lumichrome T8's. The color rendition is virtually flawless.

You say incandescents are the BASELINE for CRI comparison in the warm range of 2700-3400K. It was my presumption that a CRI of 100 was based on the color rendering index of natural daylight and not artificial. Incandescent bulbs, again according to my understanding, are not comprised of the full spectrum, so how can they possibly allow one to differentiate between colors? Even Soltec doesn't claim their lights to be 100 CRI. They say 98 or 99. I think that 2700-3400K is far too yellow anyway for my needs so I consider it a moot point.

When my students bring in their painting assignments there are always huge problems with the color, if they have incandescent bulbs in their studios. When they switch to the bulbs I recommend those problems seem to evaporate.

The bulbs I use are a near perfect match to the north light that enters my studio. during the winter months. Unfortunately there are trees outside my window that block the sky so I need additional light for the other half of the year. I sometimes continue working past sundown and never regret the nighttime color choices I've made the following morning.

It works for me.

[Kent Curole]

I'm desperate at this point. I have one of those day jobs (graphic designer) therefore I do most of my painting at night. Even when I paint on weekends, my set up still does not have sufficient light... not even near enough. I would like to make or purchase what ever is necessary to see colors correctly.

Marvin,

I'd like to know and see what type of fixtures you use your Lumichrome bulbs in. I would also like to see how you use them.

1. When painting a model live, do you use this on the model and on your painting?

2. When painting from a photo, do you have a fixture that lights the photo and canvas together?

Does any of these variable change from daytime to night, seeming as you may use daylight to light the model and or your canvas?

Thanks,

Kent

[Marvin Mattelson]

I use the Lowel Light Array (http://www.lowel.com/lightarray/) which I purchased at B&H Photo in NY. It's attached to the wall using a Bogen wall mounted boom arm (http://www.bogenimaging.us/product/t...=229&itemid=50) also purchased at B&H. You can see the pictures below.

I use this primarily to illuminate my canvas since the overall effect is very soft. I usually rig sheets to block the light from hitting the model and put a separate light on the model. I use 18 inch Lumichrome bulbs in a smaller fixture. A smaller fixture gives sharper shadow edges.

The Light Array illuminates my photo reference as well as my painting.

The color changes very little from day to night since the color temperature of the Lumichrome bulbs is closly matched to north daylight. As I mentioned earlier during the warmer months trees outside of my north window block the skylight so I really depend on these lights.

[Garth Herrick]

Marvin:

Your Lowel Light Array is awesome, and I am jealous! Someday .......

In the meantime, please allow me to share my poor man's alternative for those portrait artists on a tight budget:

I purchased a set of four 4 foot T-8 lamps from Just Normlicht in Bristol, PA.http://www.just.de/us/shop/shop.asp?...tstoffr%F6hren

They are 98 CRI, 5000 K, 36 watts, and in my humble opinion, quite good at color rendering; at any rate, the best flourescent lamps available. The set is priced at $119.00. T-8 lamps are brighter and more efficient than the fatter T-12 lamps, and have zero flicker and hum.

To run these lamps one needs two dual T-8 lamp fixtures available from Home Depot, each at $27.00 and change.

To mount these, I got a $5.00 1 x 12 x 4 foot board, and some 2 x 4's, also from Home Depot. I also picked up some electrical wire, 2 wall switches and a plug to fit a standard electrical outlet; all very cheap.

For the first time, I have daylight at night.

Garth