People saw the Sinaiticus manuscript before Tischendorf stole is and it was white.
The pages given to King Frederick ae still white. The pages found near the end of the last century were white
SO why are the pages of the New Testament Tischendorf gave to the world old looking?
This cannot be the Sinaiticus of the monastery or if it is it has been tampered with which means you cannot trust it especially when you examine mark 16:9-21 and find the pages with it on were not in the original Sinaiticus because they are not in the style of the original writing of the manuscript but has to be a later alteration.
Modern bibles are based on a fake or a codex that has been tampered with.