Photomicrography vs Spectrogram

顕微鏡写真 / スペクトログラム

Photomicrography comes from Photographic Genres and Spectrogram from Diagrammatic Expression. Both are read here as technique. They are reached for with some of the same intent, which is where they get confused.

Photomicrography

Photomicrography — ベントレーの雪の結晶 1905頃 — Wikimedia Commons / Public domainPhotomicrography — 雪の結晶 1890 — Wikimedia Commons / Public domainPhotomicrography — イブプロフェン結晶の偏光顕微鏡写真 — Wikimedia Commons / CC BY 4.0

Scientific photography that records, through a microscope, structures the eye cannot reach. Bentley's snowflakes proved the scientific image could be beautiful, and that claim runs on through polarized color and fluorescence to the Nikon Small World of today.

Spectrogram

Spectrogram — 鳥のさえずりのスペクトログラム — Wikimedia Commons / Public domainSpectrogram — ソノグラム（CC BY-SA 4.0）Spectrogram — 母音 [i][u][a] のスペクトログラム — Wikimedia Commons / CC BY 2.0

A visualization that maps sound onto a plane of time, frequency and intensity. From birdsong research to the DAW screen it became the standard way to see the shape of a sound, and artists have since taken to hiding pictures inside it.

PhotomicrographySpectrogram
Era1840s–1940s–
FamilyPhotographic GenresDiagrammatic Expression
KindTechniqueTechnique
CuesStructures beyond sight / Specimens on black / Polarized and fluorescent color / The wonder of symmetryThe time-frequency plane / Intensity as shading / Voiceprint patterns / Hidden-image play
Best used forIllustrations for outreach and science writing on research findings · Product documents that show material structure as evidenceLocating noise or overtones in a recording by eye instead of ear · Explaining how a sound changes as a single figure along time
TypePut magnification and a scale bar in the frame with the specimen nameA log frequency axis, scale and units printed inside the figure
CompositionFloat the specimen on black, turned so repetition readsTime across and frequency up, an intensity key alongside
MaterialSeparate tissues by polarized or fluorescent color and record the basisA colormap rising monotonically in lightness, never rainbow
CautionScale bar and magnification get dropped while the color is being made beautiful, and the result becomes decoration that no longer works as a scientific figure.Drawing without choosing a window length skews the tradeoff between time and frequency resolution, and artifacts get read as real features.

Put these two together

Photographic Genres ／ Diagrammatic Expression

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