Biometric fingerprint technology uses points on the fingerprint that translate into a large number string, algorithm, and that the fingerprint itself is not stored. Although on some systems used in schools an image of a fingerprint does appear on screen when initially scanned.
One can get tied up in the technicalities of the systems, as using biometrics with children poses a whole host of issues.
However fingerprint characteristics can help determine race and ethnicity. Presumably therefore classing fingerprints as "sensitive data" under the UK Data Protection Act as stated in Part 1, Section 2 (a)
"sensitive personal data" means personal data consisting of information as to-
(a) the racial or ethnic origin of the data subject
To collect sensitive data you are legally obliged to obtain specific written consent from the data subject unless you have a legal reason to collect the data. Individuals must be given sufficient information to ensure that they understand what is involved in the research and what will happen to their data.
This article that states it is possible that fingerprints can place race types:
Our society has given the genetic trait of skin colour the special privilege of being the dividing line between human races. But fingerprint types, blood types, or any one of the other 25 per cent of genes that vary among humans could just as logically be used.
A racial world based on fingerprint types, for example, would place most Europeans and Africans in the "Loops" race; Mongolians and Australian aborigines would be proud members of the "Whorls".
And more evidence here too:
...other researchers found rough correlations between fingerprint pattern type and ethnicity, heredity and even some health factors. These correlations, especially the ethnic ones, have proven robust and still hold up today
...the perceived “emptiness” and harmlessness of fingerprint patterns is a social achievement, not a natural fact.