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Introduction to Colour Accurate Lighting

18th September 2015 Colour Management & Lighting


Introduction

Colour accurate lighting is fundamental to a colour managed workflow. If you are currently viewing your prints under standard tungsten globes or standard fluorescents, then you're not seeing your prints as they really are.

Most common light sources have significant problems, either their colour temperature is too warm for a colour managed workflow (tungsten and halogen globes), or the lights have weird spectral spikes and gaps (fluorescent globes). This means that the light falling on your prints, and therefore back to your eye, is simply not the best lighting for judging the true colours of your prints.

Colour Management systems operate around the D50 reference light source. This is the light source that almost all printer profiles are built for, and is a very specific standard for lights. It defines the colour of the light (whitepoint) and the complete spectral output of the light - that is, how much of each wavelength (or colour) is being output by the light source. This very precise definition of light is chosen as the reference light source as it is a reflection of 'average' lighting condition - a mix of indoor and outdoor light, with a spectral output designed to match that of daylight, and be nearly uniform.

When you view your prints under the reference light source, you will find your screen to monitor match is significantly better than viewing your prints under typical lights. You will also find your prints tend to look better than ever before.

You can read more about light sources, and setting up your working environment in the Digital Fine Print Book. Specifically, Chapter One deals with setting up your work area, and Chapter Two discusses reference light sources.

Setting up a small print viewing area or booth

A print viewing booth is slick, professional, easy and unfortunately not cheap. However in a commercial environment these will look far superior to anything you're likely to be able to knock up easily for yourself, so they're definitely a good option. Displaying your work in one of these booths gives you the best chance to make sales as your work will never look better. It's what high end wedding photographers use.

If you want to cheaply make your own print viewing booth, it's not too hard with standard halogen fittings and a standard transformer from electrical supply stores - there are some notes in Chapter One of the Digital Fine Print notes.

GrafiLite lamps are another great colour accurate option. There are two models available - one illuminates an area a bit over A4 in size - the original Grafilite, the other an area around A3+ - the Grafilite Mode. This is a really simple system with a great quality light source. The Grafilites are standard 240V lamps complete with Grafilite colour accurate tubes. Just plug in, switch on, and be assured that you're evaluating your prints in very good quality light. We use a couple of the Mode models to light a print table for print review - this system is used mainly for art reproduction work which requires very high accuracy.

GrafiLite Lamp
The original GrafiLite colour accurate print viewing lamp illuminating an area up to A4
$159
More info

Setting up your house lighting

The best lighting for your general house or office lighting, if colour accuracy and print viewing is an important part of your work, is correct colour temperature light with an even spectral output. In most modern homes and many offices, this is now easy to achieve, as most are now built with halogen downlight fittings.

SoLux 4700K MR16 Colour Accurate Bulbs
SoLux bulbs for correct colour temperature light in your work or print viewing area.
More info

Room Lighting

If you have existing halogen downlight fittings in your room, this is a simple matter of replacing your existing globes with Solux globes. Generally, with normal height ceilings, the 50W bulbs are recommended. A typical halogen downlight ceiling fitting is shown in the picture below.

If you do not have existing fittings, you can have an electrician install these lights to replace your older tungsten or fluorescent fittings. They will install a transformer from 240V to 12V and then you can either do the 12V work yourself, or have the electrician do it. If you are installing new lighting, we recommend you have your fittings spaced around 1 to 1.5m apart at the most so that you create a more even lighting than the typical room lighting that is installed.

The Solux bulbs we sell are 36 degree lights - that is they have a fairly wide spread of light from the bulb outward, similar to the lights installed in most homes. The colour temperature and rendering abilities of the globes are best in the center, so the more even you can get your lighting the better. That said, even if you have 2 or more meters between your fittings, your lighting will still be much better and more accurate with Solux bulbs than with regular halogen downlight bulbs.

Track Lighting

If you're room lighting is based on some other type of lighting, the you can at least install some task lighting using track based systems (available from lighting stores or even Ikea) and put Solux globes in. Track lighting is a great way to install task lighting over a specific area, such as a large bench for print viewing.

Any lighting store will have a variety of fittings to choose from, just check the actual fittings are MR16 and suitable for the wattage of the bulbs you choose. You can install the tracks and lights yourself, but you will need a qualified electrician to connect the 12V transformer to your 240V wiring. As track lighting is generally lower than ceiling lighting, we find in most installations that the 35W bulbs are bright enough.

If your office home or office currently has fluorescent lighting, then you should source colour accurate high CRI full spectrum lighting. We don't currently sell these but there's some advice on which ones to go for in Chapter One of the Digital Fine Print notes. While these lights are much better than standard fluorescent lights, they are still quite some way off the quality of Solux Globes in terms of spectral output.

Really good galleries use high powered globes at a greater distance, or bounced off a white ceiling, to create bright but diffuse lighting conditions. It's the most comfortable environment for the viewer, and you get no glare marks from your prints. It's actually quite easy to set up too. You simply need 50w halogen MR16 light fittings, available in a vast variety of styles from lighting stores and some furniture stores like Ikea.

The trick is to have powerful lights that do not shine directly at the print but rather lift the ambient light level of your entire display area up to suitable levels. You can face the fittings up toward your ceiling or toward your side walls if they're painted a neutral white, or simply set the lights well back from the prints and at appropriate angles such that when any normal viewer is looking at your images they won't see flare spots.

A lot of photographic galleries set themselves up with track based lighting systems with low power halogens at 45 degree angles to prints.This lighting scenario creates an large amount of glare and flare which means your work is definitely not being displayed to its full potential - particularly for prints behind glass, or prints on semi-gloss/gloss papers.

There is another thing to remember when setting up your gallery lighting - the top of the work should line up with eye level, so hang the work so that the top is at about 5'8" or about 170cm if you're aiming for the average Australian height. This means your lighting should not be too high.