sts on 
titut 
1e ortho- 
:65.000 
sep- 
hophoto 
of 
oring 
31 
odel 
he map 
between 
recor- 
cted to 
iipped 
j are 
the 
has 
Film 
000 
; evident - 
eparing 
sks) : 
pre- 
ley 
nurse 
of 
Lettering and figures required for the contour line representation, the hydrography names 
foil, and the margin/grid foil have been prepared by photo composition and inserted into the drawing 
manually. 
By a phototechnical fading out of the foils 7, 8, and 9 (road mask, hydrography mask, 
railroad mask) from the foils 3 and 4 (forest mask, field mask), we have obtained : 
15. Forest Mask / without 
16. Field Mask / without 
By a phototechnical fading out of the foil 11 (valley mask) from the foil 4 (field mask) we 
have obtained : 
17. Field Mask Foil without Valley. 
By a phototechnical second exposure of the settlements by means of a negative of foil 12 
(settlement mask), we have obtained the 
18. Aerial Photograph Foil with accentuated settlements. 
By assembling the foils 15 (forest mask / without) and 16 (field mask / without), we have 
finally obtained the 
19. Basic Mask Foil, 
“3.3. - Screening - As is generally known, the density of the screens used in practical work 
reaches from a coarse screen with 20 lines (dot lines respectively) per cm to the very fine screen 
with 120 lines per cm. The question as to the use of the most expedient screen in photomapping 
can not yet be answered satisfactorily. Some of the aforementioned printing originals have been 
screened with a 60 dot contact screen, and with an 80 dot contact screen. Further details as to the 
screening are given in the analysis of the results obtained so far. 
3. 4. - Printing Process, Printing Paper - With the aid of the aforementioned printing originals 
and corresponding printing plates respectively, different versions of a topographic photo map can 
now be realized. Figures 1 to 5 show some versions which seem to be useful. In these figures the 
aforementioned printing originals (printing plates respectively) are indicated with their appertai- 
ning numbers. Some of the versions have already been printed. For offset printing, a Roland Ultra 
(Type RU 4) has been used, as printing paper serving either "map paper" or coated art paper. 
Further details are given in the analysis of the results obtained so far. 
  
3.5.- Results Obtained - The first test on the preparation of a topographic photo map 1:25.000 
has been performed according to Printing Process A. Of the possibilities indicated, one has been 
realized. The following version of the map sheet "Dillenburg' is available : 
A1 = 18 + (7 + 3 + 11 t: 12 + 13 + 14 
This version has already been published [5] . It does not yet contain any contour line re- 
presentation since the representation (printing original No. 2), by photographic means directly 
obtained from the Orthoprojector GZ 1, is not fit to be printed on to the map due to its low carto- 
graphic quality. The printing original No. 10, the engraving of the contour line representation, 
has at that time not yet been available. For the screening of the printing originals, a 80 dot screen 
has been used. The field mask, forest mask, and valley mask (printing originals No. 17, No. 3, 
No. 11) have been screened in order to be able to print them on the aerial photograph printed before. 
Although such a process allows a better matching of the subsequently following colours to the co- 
lours already printed, it also bears certain disadvantages. Printing has been done on coated artpaper. 
The second test on the preparation of a topographic photo map 1:25.000 has been performed 
according to Printing Process B. Of the possibilities indicated, several have been realized. The 
following versions of the map sheet "Dillenburg' are available : 
Bl =19'+ 7 +8 +90 +1 +10 + 13 + 14 
B2 = 19 + Ÿ +1 +10 +13 + 14 
B3 =19 + 7+ 8 +1 +10 + 13 + 14 
B4 = 19 + 8 +1 +10 + 13 + 14 
B5 = 19 +1 +10 + 13 + 14 
B6 = 714 8 +9 + 1 + 10 + 13 + 14 
= 29 =