Light coloured materials reflect sunlight better than dark coloured materials. On the other hand, dark coloured materials absorb sunlight better than light coloured materials. The first item relates especially to roofing, and the second to solar gain indoors using thermal mass.
This linked web page allows one to judge how much sunlight a particular colour absorbs:
http://www.colorbondcolours.com/index.cfm?objectid=8B6F92BE-F527-A741-658154CA970272AA
In the web page, Table 1 lists the solar absorptivity of named commercial colours. The extreme values of absorptance among the chosen colours are 0.31 for "Classic Cream" and 0.749 for "Deep Ocean". The second heats up more than twice as much as the first.
The table also lists the class of each colour as:
Very Light, Light, or Dark in the classification of the Building Code of Australia (BCA), and
Light, Medium, or Dark in the classification for the NSW BASIX Certificate.
The web-page above results from BASIX putting the onus on the paint producer to specify the product's absorptivity. Another paint producer, specialising in low-absorptance paints, has a similar web-site, but cites each colour's solar reflectance, which is (one minus absorptance):
http://www.solacoat.com.au/Colour-Selection-pg7808.html
A manufacturer of bricks also lists the solar absorptance classes of over 100 product lines, unfortunately without colour samples of them:
http://www.australbricks.com/Sustainability/Thermal-performance-ratings/Solar-Absorbance-Ratings
Classes Dark, Medium and Light are assigned, said to be indexed so as to suit NatHERS software. I can find no helpful links, nor mention of these classes on the NatHERS site.
Building Code of Australia
I cannot find any statement on the web by the BCA giving their rules for roofing absorptivity (they want you to buy the Code). There is second-hand information on this page:
http://www.truecore.com.au/files/dmfile/SustainabilityTechBulletinUrbanHeatIslandsJuly2010.pdf
For residential buildings the BCA absorptance classes are: Very light, less than or equal to 0.4; Light, less than or equal to 0.6. For some reason (political?) the classes for Commercial buildings allow much more absorptance: up to 0.5 and 0.8. (Can an absorptance of 0.8 be called "Light"?)
BASIX
The BASIX requirement is here:
http://alts.basix.nsw.gov.au/alts/WebHelp/construction/ceiling_and_roof/roof_colour_or_solar_absorptance.htm
In BASIX, Light colours have solar absorptance less than 0.475, and Dark colours have solar absorptance greater than 0.70. BASIX is a system intended to bully people into using common sense.
"BASIX requires roof insulation for a dark or medium coloured roof." So what do people do? As they have already decided to install insulation "because everybody does", they then choose dark colour roofing because BASIX permits it!
Colours for high solar absorptance indoors.
The brick manufacturer above pushes the line that some light-coloured bricks help to keep the house cool. They seem not to appreciate that darker colours might be useful for thermal mass materials for winter solar gain.
I have checked the colours that I have used for this purpose, using the Munsell color system:
http://en.wikipedia.org/wiki/Munsell_color_system
My floor tile colour is 5YR4/4, and my interior double brick wall is 5YR5/4. Both may be termed "Moderate Brown". In the Munsell system the first number after the letters is the Value (or Lightness) on a scale from 1 for black to 9 for white. My materials are thus about mid-way on the scale. I felt that darker colours would not look good.
I have not found the relation between Munsell color classes and solar absorptance. It probably is not quite the same Value for different Hues. However, Munsell Values of four must have solar absorptance near 0.6.
