In the old days of radio broadcasting when we used material from various and questinable sources, audio correspondants would often use their domestic 4-track machine to record their radio contributions. Likewise being on the move the head azimuth would often go out of alignment resulting in having to plead with engineers to do their best to resusticate such material.
There was an American product which usd to provide a few glass slides, cotton buds, alcohol and a 'developing fluid'. What one would do is immerse a portion of the tape in the liquid and then view the resulting 'developed' tape under a magnifying glass where you could view how the head alignment looked for that particular audio section. Obviously you took the gap areas and not the main squence.
Obviously there was more to it than just that but these boffins saved many a valuable contribution from being rejected outright or being eq to the point of telephone quality.
Does anyone out there have any idea what this chemical could have been.
I am sitting with piles of 4 track tapes, crosstalk and mould for Africa and would welcome a little chemical assitance when the audio drifts in and out of alignment.
It's a long shot but someone somewhere may just have a clue as to what this chemical was. The ad on the box was typical of it's time...husband holding up developed tape and wife (in background) smiling like my man the genius.