There's a massive difference between substantive dyes and those that require mordanting.
The thing is though that even substantive dyes do a lot better when applied to protein fibres, and much better again when those are also mordanted.
This has been known since antiquity, even if the chemistry was not understood, per se.
The beautiful woven tapestries of Europe were made using only three colours. Red, yellow and blue (they did add silver and gold threads though).
Those three primary colours are all from dyes which are strong enough, and light fast enough, to over and under dye each other.
Madder, weld and indigo (whether from woad or indigo itself, it's immaterial, it's the same dye) give the red, yellow and blue, and from those the whole range of colours is available, if the dyers are good.
Medieval tapestries are still richly coloured today
There's another thing about those old wool and silk tapestries too, the weavers do not thread through the loose ends and cut them off; the ends of the weft threads are left to hang down the back of the tapestry, and since the backs were covered with linen, those wefts have been protected from damage (and light) for hundreds of years.
Restoration means restoration of the back of the tapestry too, and when the linen is removed the original colours of the threads are revealed.
The colours are bright, crisp, deep and clear
The stains used in microscopy are varied depending on the 'trade'
Iodine is used for starches, malachite green for spores, and osmium tetroxide for lipids (the fat from milk/cheese sometimes found on wood and ceramics in archaeology) while flurorescent microscopy uses rhodamine.
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