Colour Sorting

Colour sorting is a sophisticated process which enables goods to be sorted, not only by their visual colour but also according to their infra-red reflectance signal. The colour sorter is capable of viewing light reflectance differences that are outside the range of the visible spectrum thus enabling sorting of inorganic contaminants such as stones and soil even when their visual appearance is similar to that of the seed in question. It can of course also be used to remove discoloured and foreign seeds from the product by their visual appearance as well. This is the only process that would be capable of removing foreign seeds that are of a similar size and shape to the product.

We have two colour sorting machines; a Satake tri-colour and a Sortex bi-chromatic Z Series. Both machines record light reflectance from the product using a number of different wavelengths of light, therefore creating a view that is similar to full colour vision. The machine plots the feedback of the signals on a graph enabling us to accurately define the signal levels in all wavelengths that denote an acceptable range of colour and those that denote material to be rejected. We are therefore able to accurately set the reject boundaries.

It should be noted that whilst the machine is able to reject accurately anything that is outside the required colour range, some seeds naturally have a mix of colours present and the colour sorter has to therefore accommodate a wider range of colours which can reduce the effectiveness of the sort.

Some of the more common products that we colour sort include:

• Adzuki Beans
• Alubia Beans
• Amaranth
• Baby Green Lima Beans
• Baby White Lima Beans
• Beluga Lentils
• Black Barley
• Black Kidney Beans
• Black Lentils
• Black Quinoa
• Black Rice
• Black Turtle Beans
• Blackeye Beans
• Borlotti Beans
• Brown Beans
• Brown Linseed
• Brown Rice
• Buckwheat
• Bulgur Wheat
• Butter Beans
• Channa Dall
• Chia Seed
• Chick Peas
• Coriander
• Cracked Freekeh Wheat
• Cranberry Beans
• Cumin Seed
• Dark Red Kidney Beans
• Dark Speckled Green Lentils
• Desi Chickpeas
• Flageolet Beans
• Freekeh Wheat
• Golden Linseed
• Great Northern Beans
• Green Lentils
• Gunga Peas
• GWS Pumpkinseed
• Hemp Seed
• Large Lima Beans
• Maize
• Maple Peas
• Marrowfat Peas
• Millet
• Mung Beans
• Mung Dal
• Peabeans
• Pearl Barley
• Pearled Spelt
• Pinto Beans
• Popcorn
• Poppy Seed
• Pumpkinseed
• Red Quinoa
• Red Rice
• Red Split Lentils
• Rosecocoa Beans
• Rye Berries
• Sorghum Seed
• Spelt Wheat
• Sunflower Seed
• Toor Dall
• Urid Beans
• Urid Dall
• Wheat Berries
• White Quinoa
• White Rice
• White Maize
• Whole Brown Lentils
• Yellow Split Peas

To view the full range of processing services that we offer, click here.

If you would like further details on our colour sorting service, or to discuss your processing requirements then please do get in touch on 01223 834100 or hello@granta.uk.com.