Figures index

From

Diazotype – A Historical Copying Process

Matthias Ducci

World Journal of Chemical Education. 2021, 9(4), 136-143 doi:10.12691/wjce-9-4-6
  • Figure 1. Structural formulae of picramic acid (left) and 2-diazo-4,6-dinitrophenol (right)
  • Figure 2. Ionic (top) and radical (bottom) C-N bond cleavage.
  • Figure 3. Sequence of photolysis and subsequent phenol formation after ionic decay of the excited singlet diazonium cation (modified according to [11])
  • Figure 4. Acidic (left), neutral (middle) and alkaline 5-ASA solution under UV light (λ = 365 nm). (Photographs: Ducci)
  • Figure 5. Equilibria of 5-ASA in aqueous solution
  • Figure 6. 5-Diazosalicylic acid. (Photograph: Ducci)
  • Figure 7. Thermolysis of 5-diazosalicylic acid. The time between the two images was 1/25 s. (Photographs: Ducci)
  • Figure 8. Diazotisation of 5-ASA and formation of 5-diazosalicylic acid
  • Figure 9. Diazonium salt solution under UV light (λ = 365 nm; top: immediately after dropping the solution onto a filter paper; middle: after 5 seconds; bottom: after 45 seconds). (Photographs: Ducci)
  • Figure 10. Left: Photochemically generated image using a fern leaf under UV light. Right: The same image after prolonged irradiation with UV light (λ = 365 nm). (Photographs: Ducci)
  • Figure 11. Irradiation of the diazonium salt solution leads to the formation of gas bubbles of nitrogen. (Photograph: Ducci)
  • Figure 12. Illustration of photolytic nitrogen removal with subsequent formation of 2,5-dihydroxybenzoic acid with structural formulae
  • Figure 13. From top to bottom: Original photo (Ducci), printout as black and white image on foil, image obtained by diazotype, same image under UV light (motif: East Side Gallery Berlin/Germany)
  • Figure 14. Coupling reaction with phloroglucinol
  • Figure 15. Top: Diazotype with a red azo dye (motif: Temple of Augustus, Pula/Croatia); bottom: Foil print used.
  • Figure 16. Top: Diazotype with yellow azo dye (motif: Traditional Turkish houses in the centre of Ankara/Turkey); bottom: The same image under UV light (λ = 365 nm)
  • Figure 17. Diazotype with a mixture of a yellow and a red azo dye (motif: Giant Ferris Wheel in the Vienna Prater/Austria)
  • Figure 18. Concurrent syntheses ((a) with 2-naphthol and (b) with resorcinol) of a red (a) and a yellow (b) azo dye, yielding the mixed colour orange in Figure 17
  • Figure 19. Diazotype with a blue azo dye (top), which takes on a reddish-brown hue at a lower pH value (outgassing of ammonia) (motif: Kaiser Wilhelm Bridge, Wilhelmshaven/Germany)
  • Figure 20. Azo dye with 2,2'-dihydroxy-substituted azo compound
  • Figure 21. Diazotype with ammonia under triazene formation (motif: Brandenburg Gate, Berlin/Germany)