Everything the Artist Needs to Know About Lighting in the Studio or Gallery - Types of Lighting (Part 3 of 5)
The type of lamp or bulb you choose has a significant bearing on the quantity and quality of light you can obtain. A range of options are available to improve existing lighting. Desk lamps are cheap enough that you can have several types of lighting available, and avoid the need for an electrician to wire in fixed fittings.
For the average artist, a good lighting arrangement can be easily achieved. An adjustable desk, clamp, or floor standing lamp fixture which can direct light onto your work is a cheap investment (if you shop around). Fitting these with a 100Watt daylight corrected incandescent bulb means you’ll have accurate colour rendition for proofing, and a colour temperature similar to around 2 hours before midday.
The same arrangement can be used for lighting your subject matter (if it is small), though for lighting larger subjects you’ll need to ideally invest in photographic lighting systems. These systems are beyond the scope of this article, though well covered in many photographic websites.
Like me, it is anticipated that the average reader of this article will wander down to the nearest lighting shop for cheaper alternatives. Unfortunately not all bulbs are created equal, and neither is the knowledge of most employees. Accordingly I hope to give you a guide to what you should and should not use, (or so you can outshine one of those assistants who claim to know everything but actually know very little).
Best cheap upgrades to existing lighting in a studio or gallery:
- replace incandescent (old style) bulbs with daylight corrected incandescents;
- replace compact fluorescents (energy savers) with daylight corrected incandescents if colour reproduction is important;
- replace old fluorescent tubes with newer triphosphor tubes with an 8xx or 9xx rating (see below);
- buy a desk/floor/clamp light for directing onto your work and install a daylight corrected incandescent.
- Replace incandescent reflector bulbs in spotlights with xenon-halogen bulbs (where UV is a problem either use xenon, or a halogen bulb with a built in UV filter);
- Believe what’s written on the box, over what the salesperson says.
Lighting Types & Characteristics
Daylight incandescent
Lighting your work
Lighting subject
General area lighting
Pros/Cons
Cheap, very good colour rendition
Good colour temperature
Normal incandescent
Lighting your work
Lighting subject
General area lighting
Pros/Cons
Cheap, very good colour rendition
but poor colour temperature
Halogen
Lighting your work
Lighting subject
General area lighting
Pros/Cons
Cheap, excellent colour rendition
but low colour temperature
Xenon-Halogen
Lighting your work
Lighting subject
General area lighting
Pros/Cons
Cheap, excellent colour rendition
but low colour temperature
Compact Fluorescents (energy savers)
General area lighting
Pros/Cons
Cheap to buy and run
Poor colour rendition except
full spectrum models
range of colour temperature
Fluorescent tubes
General area lighting
Lighting subject
Pros/Cons
Relatively Cheap if you have fittings
use 8 or 9 series models (see below)
choice of colour temperatures
older unrated tubes should be upgraded
(unrated - i.e. no 8xx or 9xx specification on tube)
Xenon Flood/discharge
Lighting subject
Pros/Cons
expensive specialist product
Excellent colour temp & rendition
often used for photographic work
use where good lighting critical
There are two main types of lighting in a studio – work (task) lighting and general area lighting. If you are fortunate you will have both, and should try and reach this ideal as soon as possible. General area lighting stops you bumping into things, and being able to find where you put your paint brush. Colour reproduction may be not so important, but upgrading your bulbs to give better colour reproduction is a good investment – often you will want to inspect things other than on your working area.
Task lighting is localised and should be able to be directed onto your work area, as well as any proofing and review area. You will need to decide what suits your work habits – localised lighting may be as simple as buying a desk lamp or clamp light fitted with the appropriate bulb/lamp.
Fluorescent tubes provide good even lighting over a large area. Some tubes give very good colour reproduction – providing you know what you are looking for. Upgrading existing fluorescent tubes can be a cheap upgrade for even lighting, at a colour temperature of your choice, and with good colour rendition (reproduction).
luorescent tubes use phosphors (the white stuff on the inside of the tube) to produce light. Fluorescent phosphors (less so at the budget end) are often formulated to give good colour reproduction – this is due to demands in retail. Most good quality daylight or warm tubes will give a full spectrum light allowing for good colour reproduction.
So which tubes do you need? Ideally you will want to specify 835, 840, 930 or 965 fluorescent tubes. The last two digits represent the colour temperature in Kelvin (e.g. 35 means 3500K) which gives you a great choice of colour temperature.
The first number represents the accuracy of colour reproduction/rendition (and in some ways reflects the colour spectrum of the light source – see earlier article). An 8 series tube gives very good colour reproduction, while a 9 series tube gives excellent colour reproduction (and is typically used in photographic light boxes). 10 is the theoretical maximum under the current scale and currently is only achieved by full spectrum filament lamps such as the traditional incandescent lamp, and many low voltage halogen and xenon lamps (though colour temperature can be a limitation). The scale for color rendition is the Ra – hence a 9 series tube has an Ra in the 90s, an 8 series tube has an Ra in the 80s. Incandescent lamps typically have an Ra of 100, as does sunlight. The higher the number the better.
At the lower end of the budget, a standard fluorescent tube fitting with 840 tubes (these are the most common tubes available which have a rating) is adequate for general area lighting in most art studios. If there is no rating on the tube, don't buy it.
Compact Fluorescent Lamps (CFLs or Energy Savers) do not normally publish information about the spectrum, and sometimes not about the colour temperature (other than ‘warm’ or ‘cool white’). As these are made by a variety of manufacturers, whose choice of phosphor (and hence colour spectrum) may be dictated by phosphor cost, or brightness per watt, CFLs are not generally recommended for when accurate colour rendition is important or colour temperature is critical. The exception is the relatively uncommon full spectrum CFLs. As a general rule CFLs are good for energy efficient general lighting when you don’t have the choice of fluorescent tubes, but daylight corrected incandescents will give better colour rendition and should be used in more critical areas of your studio.
Low voltage halogen (and xenon) bulbs can make good work lighting and most low voltage types are full spectrum, but do not provide for much choice in color temperature values – you are typically limited to around 3000-3500K though Vivalite produces a 5000K low voltage halogen lamp. For work which will be exhibited under this type of lighting, having these bulbs present in the studio can be useful. Desk and clamp lights which accept halogen bulbs are cheap and readily available.
Mains voltage halogen lights appear to be less bright, and less energy efficient than low voltage equivalents, but the newer mains xenon-halogen replacements appear to address many of these limitations. Currently, low voltage halogen lamps are still preferable. If you are fitting new lights, you are probably better to choose fluoresent tubes, or low voltage halogen fittings with xenon-halogen bulbs.
Incandescent lights, despite their obvious colour cast, actually produce a very good spectrum of light. The better solution is to use a Daylight Corrected Incandescent Bulb, which is made by a number of manufacturers. It looks like a clear incandescent bulb with a clear blue coating on the glass to remove excess red-orange from the emitted light spectrum and thus increase the colour temperature. I have one of these in a desk lamp and have found it to be about the best (cheap) solution for reviewing and proofing work (as well as for working under). The bulb I bought today cost under NZ$7, and was available in both bayonet and Edison Screw fittings. The problem with incandescent bulbs is poor lifetime and poor energy efficiency. However, if good colour reproduction is required and existing fittings take this type of bulb, then you are probably best to buy and install the daylight corrected incandescent bulbs.
LED lamps. Probably best to stay away from these currently – at the moment there is very little data about the spectrum and colour temperatures of this form of lighting. They also come from a wide variety of sources, with different levels of quality control. Unlike single colour LEDs, most white LEDs actually use an internal internal UV LED to excite a white phosphor. Here we run into the same problem as most non-‘full spectrum’ Compact Fluorescent Lamps – one is never quite sure about the spectrum of the light from the phosphors chosen. However this is likely to change as LEDs become more popular as a mainstream light source, and it is increasingly used in specialised areas such as museums and galleries. If you find an LED lamp with specifications indicating it is full spectrum, then by all means consider it, though low voltageLED lamps often require special control gear (and many cannot be directly substituted for a low voltage halogen lamp unless a wire wound transformer has been used)
What do I have in my studios? I have several downlights with higher end compact fluorescent bulbs for general area lighting. Over my drawing desk I have halogen ceiling downlights fitted with low voltage xenon-halogen bulbs, which are brighter than halogens and produce minimal UV light - you are likely to see these being more common place in galleries until LED lamps take over. I also have, on my drawing desks, desk lamps with Daylight Corrected Incandescent Bulbs for working, proofing, and reviewing.
If you can, it is best to have a variety of light sources to emulate the conditions under which your work will be reviewed. Also, there is no perfect substitute for the sun, whose light characteristics also change during the course of a day and due to atmospheric conditions. Having a range of lighting can help you simulate different effects, and allow for reasonably accurate colour rendition under different colour temperature conditions.
Examples of detailed lamp data sheets:
Mains halogen http://www.lampspecialists.co.nz/productPDFs/5255h.pdf
CFL energy savers http://www.lampspecialists.co.nz/productPDFs/5224h.pdf
Low voltage halogen http://www.lampspecialists.co.nz/productPDFs/5257h.pdf
Fluorescent tube http://www.lightaudit.com/data/phillipsfluorescent/master_tel5_high_efficiency.pdf
article image - www.hughmitton.com
