Difference between linotype/monotype/manual composition after printing?

One thing to look for as a Linotype tell-tale is poor kerning. Look for a capital W beside a lowercase letter, if there is a glaring white space, there is a chance the text was set on a Linotype. Italic text set on a Linotype also suffered from this limitation.

If the linotype mats were well-worn, you can sometimes spot ‘hairlines’, fine lines that appear between the letters on the printed page.

In text with fully justified lines, because of the use of spacebands, the width of spaces of Linotype produced text will be identical on each line, whereas with hand set text the distribution of spacing material couldn’t always be perfectly uniform. I don’t know enough about the Monotype justification system to speak knowledgeably about it in this context.

Some typefaces were machine specific, so if you can identify the face you might be able to identify how the type was produced.

I’d love to add the linotypes to my Linotype registry, if you’d be willing to share the serial numbers.

If there exists a list of which faces that the Linotype and monotype casters had available, you may be able to correlate that to printed works, once you identify the type. Some faces were available on monotype which were not on Lino. Same should go for hand-set.

As keelan says, worn Linotype mats produce slugs with hairlines between letters; the wear can also cause the vertical alignment of the characters to vary.
Linotype did sell special typographic refinements for many book faces, with two- or three-letter combinations on one mat, so spacing is not always an indicator. (Not just the usual fi, ff, fl, ffi, ffl ligatures, but combinations like To, Wa, fo, ft, of, etc.) The lower case italic f is a good place to start looking for either constrained design on a single-letter mat, or use of refinement mats. However, I don’t think the accents used in Brazilian Portuguese would fit on many of these refinement mats.
Poorly maintained Linotypes can also produce slugs that taper from side to side, so one side of a text block is deeper than the other. And in poor lockup of the form, Linotype slugs can also be off their feet in a way that ascenders or descenders print darker or lighter, where with Monotype or hand-set type, type goes off its feet horizontally. Also, work-ups of spaces wouldn’t happen with Linotype slugs.

Thank you all for your help! @keelan, here are the serial numbers and the data I could found until now. They were all taken from the inventory that was done by the occasion of the company bankruptcy in 1925.

By the way, the firm was called Companhia Graphico-Editora Monteiro Lobato, based in São Paulo.

Screen Shot 2019-07-28 at 18.42.19.png

I agree with Keelan that you should try to identify the type face and then match it up with specimens for Linotype vs. Monotype vs. foundry type. From your later post it sounds like this company went bankrupt in 1925, so the timeline reduces a lot of overlap in type faces that were later copied fast and furiously between the different formats, but with sometimes subtle differences. In 1925 Linotype and Monotype had much more limited ranges of type faces than in later years, although I’m sure many of them were based on existing foundry designs.
Matt