Engineered Stone: Shade

Engineered stone is technically known for a homogeneous shade, that is not entirely true. Engineered stone producers publicize that they guarantee same shade, however in big quantities I figure it's very unlikely, due to several factors that effect shade.
What factors may effect the shade of my engineered stone?

• Slab Production factors: during the daily production several batches of raw materials are mixed together, and when dealing with white or beige type colours, little changes may occur that can affect the colouring, namely:
• error in pigment quantity: I know this sounds awkward, but in reality to make a certain colour we normally mix several pigments together, and some are very concentrated and the quantity can be grams ... so being of by a few grams of concentrated blue, may turn your light grey into a light beige;
• exchange on the discharge sequence into the mixer: for those of you familiarized with these production facilities, mixing is one of the most important parts of the process, you may think that every producer has the pigment sequence made by machines .... what if I told you that some producers do it manually .... human error may occur
• raw material quality: in truth when you grind hundreds of tons of quartz, you'll surely have a few tons with a slightly different shade, when producing this factor may cause a slight shade difference between batch productions
• Cleanliness: image a big mixer which just ended a production of a black quartz .... the next step is cleaning, but it's done manually, so the next batch will certainly have some impurities from the batch before. 

• Polishing: people might not give it the importance it deserves, but in my opinion it's where most of the shade problems occur. It can be due to the following: 

• Change in the abrasive sequence between 2 productions: in truth great part of the shade variations arise from the different gloss points the material may have, this can cause uneven slabs, making the tiles cut from the same slab different in shade.
• Production variables: producing with different variables, namely water quantity or velocity of the production line
• Chemical enhancement: some production lines have a chemical applicator, the objective is to enhance the products physical properties and consequently may also affect  the gloss

It's more likely to have a shade problem with you supply when dealing with tiles, especially if the project is big and has to be produced with several batches. When dealing with countertops, it can also occur, depends on the attention the fabricator has regarding these issues, he can easily avoid them by using the same batch material for the job.