# Photographic reference scale **URL:** \ **Category:** Nature Talk\ **Created:** [August 11, 2022, 2:30pm UTC](https://forum.inaturalist.org/t/photographic-reference-scale/34365 "2022-08-11T14:30:21Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![queercussp](https://sea2.discourse-cdn.com/flex016/user_avatar/forum.inaturalist.org/queercussp/32/23852_2.png) [@queercussp](https://forum.inaturalist.org/u/queercussp)\ **Post date:** [August 11, 2022, 2:30pm UTC](https://forum.inaturalist.org/t/photographic-reference-scale/34365/1 "2022-08-11T14:30:21Z")
Some time ago I wondered if my observations were lacking a scale so I made a small reference inspired in the forensic ones and wanted to share it. The size is small enough to carry in most phone cases (10x5cm). I use it to measure [fishes](https://www.inaturalist.org/observations/128884133), [small insects](https://www.inaturalist.org/observations/126852742) and [under a petri dish](https://www.inaturalist.org/observations/129680769) for background. You can dowload it [here](https://drive.google.com/file/d/1amowmG0WJnJQVICmZIES-r595O_EzbYJ/view?usp=sharing) or [here](https://drive.google.com/file/d/1BaxaadKoNRxJfl-32yH-CqCWJX5TJljh/view?usp=sharing) ready to print. What are your thoughts? Do you find it usefull? [https://forum.inaturalist.org/t/fingers-in-photos/30145](https://forum.inaturalist.org/t/fingers-in-photos/30145) [https://forum.inaturalist.org/t/encouraging-a-sense-of-scale-in-photos/4147](https://forum.inaturalist.org/t/encouraging-a-sense-of-scale-in-photos/4147) ---
**Author:** ![robertarcher397](https://sea2.discourse-cdn.com/flex016/user_avatar/forum.inaturalist.org/robertarcher397/32/57_2.png) [@robertarcher397](https://forum.inaturalist.org/u/robertarcher397)\ **Post date:** [August 11, 2022, 2:55pm UTC](https://forum.inaturalist.org/t/photographic-reference-scale/34365/2 "2022-08-11T14:55:39Z")
A scale is good. But in some areas it will not be always obvious and this should also include mm., cm, lines or inches. ---
**Author:** ![ekmes](https://sea2.discourse-cdn.com/flex016/user_avatar/forum.inaturalist.org/ekmes/32/2033_2.png) [@ekmes](https://forum.inaturalist.org/u/ekmes)\ **Post date:** [August 11, 2022, 4:48pm UTC](https://forum.inaturalist.org/t/photographic-reference-scale/34365/3 "2022-08-11T16:48:08Z")
This does look very useful, thanks for sharing! May I also recommend the [Life to Scale project](https://www.inaturalist.org/projects/life-to-scale)? :) ---
**Author:** ![jciv](https://sea2.discourse-cdn.com/flex016/user_avatar/forum.inaturalist.org/jciv/32/1779_2.png) [@jciv](https://forum.inaturalist.org/u/jciv)\ **Post date:** [August 11, 2022, 9:23pm UTC](https://forum.inaturalist.org/t/photographic-reference-scale/34365/4 "2022-08-11T21:23:39Z")
After printing, compare to a real ruler to make sure it came out at the correct size. ---
**Author:** ![vreinkymov](https://sea2.discourse-cdn.com/flex016/user_avatar/forum.inaturalist.org/vreinkymov/32/58876_2.png) [@vreinkymov](https://forum.inaturalist.org/u/vreinkymov)\ **Post date:** [August 11, 2022, 11:10pm UTC](https://forum.inaturalist.org/t/photographic-reference-scale/34365/5 "2022-08-11T23:10:40Z")
Good job! I think it’s great that you created a custom scale. Is it paper with lamination? In cases like [a petri dish](https://www.inaturalist.org/observations/129680769), where scale dimensions cannot be inferred from the ruler marks, maybe adding a note stating that grid has 5 mm spacing would be helpful? ---
**Author:** ![vreinkymov](https://sea2.discourse-cdn.com/flex016/user_avatar/forum.inaturalist.org/vreinkymov/32/58876_2.png) [@vreinkymov](https://forum.inaturalist.org/u/vreinkymov)\ **Post date:** [August 12, 2022, 5:31am UTC](https://forum.inaturalist.org/t/photographic-reference-scale/34365/6 "2022-08-12T05:31:26Z")
Thankfully, if the markings are visible on the ruler edge, it’s easy to infer the scale. If there are 10 divisions (spaces between dark marks) between major marks, it’s a metric/mm ruler 99.9% of the time, whereas if there are 2, 4, 8, 16, 32, etc. divisions it’s imperial/inches. Still waiting for that 0.1% observer who carries around an imperial machinists ruler that divides inches into 10ths, that would be confusing for sure! ---
**Author:** ![system](https://us1.discourse-cdn.com/flex016/uploads/inaturalist/original/2X/7/7831452cf7f0d653ff1ffd34176334b7ef1b6a17.png) [@system](https://forum.inaturalist.org/u/system)\ **Post date:** [October 11, 2022, 5:31am UTC](https://forum.inaturalist.org/t/photographic-reference-scale/34365/7 "2022-10-11T05:31:46Z")
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