This is how I created a faux phosphate finish on my hood latch.
This finish is typified by the OEM coating on GM hood hinges that has a somewhat crystalline metallic element to it and is dark to medium dark gray in color.
This method produced acceptable results for me, but may not be suitable for an all-out restoration.
[Vehicle: '73-'77 Cutlass]
One of the pictures shows how the part compares to underhood surface painted with straight semi-gloss black lacquer Dupli-Color #DAL 1608
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There may be a commercial kit or paint for this, and perhaps someone else has figured this out, but.... I found a way to somewhat replicate the phosphate coating on some underhood parts, like the OEM coating on GM hinges, which I believe to be Zinc phosphate.

I was able to use paints I already had on hand.

• Assuming a cleaned/stripped and dry part;
• Prime with self etching primer
• Paint with Semi-gloss black lacquer
• Apply thin somewhat sparse coating of 'Graphite' (colored) wheel paint, sprayed from a distance.

(normal painting procedures apply, No. of coats, time between coats etc.)
(do not force dry, with high heat source, parts with springs still attached)

I didn't have any, but a final coat of semi-gloss clear lacquer might not be a bad idea. One would have to experiment with that to see if it helps or hurts.

The paint I used (all Dupli-Color products)

DAP 1690 Self Etching Primer (lacquer)
UPC 26916-94690

DAL 1608 Semi Gloss Black (lacquer)
26916-93608

HWP 102 Graphite [ A wheel paint ] (presumeably lacquer (?))
26916-00102

 

Eastwood spray gray and zinc phosphate rattle can paints are worth trying also.

 

nice Job!!

 

That looks nice. The only thing I would suggest is that for a closer-to-OEM finish I'd use a dead flat clear. Real phosphate coating is completely flat with a "rough" finish. The semi gloss is probably more durable but looks to shiny.