Heritage Science

Table 5 The maximum, minimum and average number of colloidal silver particles found in TEM images of historical photographs both surrounding the silver particles and in the upper layer of the cross section

From: A study of the relationship between the migration of image silver and perceived yellowing of silver gelatine photographs

Sample	Maximum^a	Minimum^a	Average^a
Street scene	397	6	130^b
Ceremony	2840	80	1197^c
Aeroplane	281	4	75^d
Crumpled manuscript	201	3	37^c

^aRelates to number of colloidal silver particles, defined as having a diameter of 0–25 nm
^bAverage of 9 values (six filaments and three from the upper layer of the cross section)
^cAverage of 11 values (nine filaments and two from the upper layer of the cross section)
^dAverage of 12 values (nine filaments and three from the upper layer of the cross section)

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