Someone I've been advising asked me a question about what colour to paint his north facing dining room. I've never met him or seen his house. He told me he wanted to use Little Greene paint - a great choice as it's one of the best quality British paint brands out there.

I emailed him a quick, and necessarily vague reply, which included the following paragraph:

"Choosing colour is the most subjective part of the job. It depends what kind of mood you want in the dining room.

Something bright and airy? Cool colours? Warm colours? Something intense for intimate dinner parties?

When will you be using the dining room? Mainly at night? If so, will you only really be looking at the colours under artificial light? What kind of lighting do you have? Tungsten or halogen (both of which are warm), fluorescent (which is usually a little cool, often with a slight green tinge) or LED (which can be either warm or daylight bulbs). [I should have included candlelight, which is very warm, of course.]

A north facing room may get no direct sunlight, just that reflected from the sky or buildings/vegetation opposite. If it's just getting skylight the light coming in will be diffuse and blue. If there is reflected light from vegetation too it'll still be mainly blue, but with green hints. If there is a large brick building opposite, reflecting strong sunlight, you may get a whole range of colours including warm tones from the brick, green tones from vegetation, blue tones from the sky. "

As you can see, I didn't give him any recommended colours. There are some lovely colours in the Little Greene palette, and they can mix more colours than they have in their colour cards. 

But my vague reply will, hopefully, give him food for thought. I've asked him lots of questions, and only with replies to those questions will we be able to move forward towards colour choices. 

Choosing colours to paint rooms, or furniture is tricky. There's so much to take into account. What effect are you looking for? What kind of light will you be seeing reflected from the painted surfaces? How will it change throughout the day, and at night? How will it work with existing furniture, or artwork, or floor coverings? 

As both a decorator and photographer I'm working with colour and light every day. I've got a pretty good idea of light quality, quantity and temperature. I bring all this experience to play when advising customers about paint colours (and paint sheen too - just to add another factor into the mix). 

But everyone is different. Each customer has different taste (thank goodness, or my work would be rather dull). Some people love the journey of choosing colours, others find it a real drag. Some people make a decision in seconds, others can take weeks, even months. 

Once you've sorted out your variables - light, mood, sheen etc. Then you can begin choosing colours. I always advise painting out large colour swatches on lining paper, and sticking them up on different walls. Looking at those swatches at different times of day, and at night. Of course to be totally sure you'd need to keep in mind season - as the angle of the sun will vary throughout each day in the year. 

No wonder many people get professional interior designers to choose colours for them, if they can afford it. It's not an easy task. If you employ a professional decorator then she/he may be able to advise - but not all decorators (even those who are highly skilled technically) will have that more artistic eye to advise. 

Colour advice is something I always offer my customers. But even if I'm offering to help choose colours, I'll always say what my preferences are, and why - but it can only be a preference. Everyone is different. 

This is how I like to do colour swatches. BIG! Farrow and Ball colours on the left, and Little Greene on the right.