Dating Vintage Sewing Patterns might become just a bit frustrating, if you're not willing to put in a wee bit of effort. To make it simple though-know despite even your best efforts-you may not be able to date vintage patterns without guesstimating in the end.
For the most part, the oldest sewing patterns aren’t dated because at the time makers didn’t believe it was important to date patterns or the envelopes-just it just wasn't done.
Luckily for all of us-this is most vintage sewing patterns are in the public domain today.
First, check the sewing pattern over completely. If there is a date most likely it's located on the pattern envelope's front, back, pattern flap or on the guide sheet.
Even though some sewing patterns, in particular apron patterns, were manufactured over a span of years, postage stamps are good sources of information when it comes to dating.
Check with the USPS for more information on dating mail stamps.
Pattern manufacturers often advertised in newspapers, books and pattern catalogs (for example, McCall’s and Vogue Pattern Books). Skim books and use the pattern number and manufacturer as starting points when researching old newspaper archives, books and magazines.
Take note of the magazine's publishing dates and any other information included ads that may offer hints.
The most unlikely tools I’ve come across when investing pattern dates come from
items tucked inside sewing patterns I've picked up at estate sells. Buttons, fabric remnants, old store receipts and newspaper clippings provide a wealth of information.
Google has a patent database. Check it out to see what information you can uncover byway of generic searches for sewing patterns by manufacturer and number.
Over time makers changed the appearance of their sewing pattern envelopes to attract buyers. Illustrations, photographs, drawings, font, fashion styles (and even the colors and information) on the front and back of patterns offer hints on dates. Use similarities and differences of the same pattern manufacturers over a span of years or the same years to get clues.
Price is helpful in dating patterns. Lower priced patterns tend to be the oldest; however vintage Vogue had prices as high as a 1.00 in the 1920s-be careful.
Designer vintage sewing patterns manufactured in conjunction with well-known fashion designers of the time can help decipher dates, but it gets tricky.
For example- French designer, Jean Patou died in 1936, but his designs were featured on Vogue sewing patterns in the 50s and 60s. Most likely, in this case Patou sewing patterns will not date earlier than the 50-60s---leaning most favorably towards the 1960s. Vogue is the only manufacturer of Patou patterns--and didn't begin its lines featuring well-known designers until the 50s-60s.
The point is- use the designer information to a limited degree in conjunction other research.
In the end it might be virtually impossible to determine a date exactly, but with a little work and research you can come up with a good educated guess.