The fonts included in this package produce X dimension at 10 mils (1/1000th inch,
or 0.0254 cm) and heights at 1/8"(XXS), 1/4"(XS), 3/8"(S),
1/2"(M), 5/8"(T), 3/4"(XT) and 1"(XXT) respectively when
printed at 12 points. To have the human readable printed beneath the barcode,
use the human readable version which has a trailing capital A in the typeface name.
Thus, MRV Code39MA prints code39 barcodes at 1/2" hight
and 10mils as X dimension, with human readable text beneath the barcode.
To simplify the size calculation, X dimension is independent of the typeface. All fonts produce barcodes with identical X dimension under the same font size. To determine the typeface and font size, first calculate the font size from X-dimension requirement, then select a typeface which closest matches the required height.
The scalable fonts in this package have different characteristics from the ones in Morovia Code39 Fontware 4.0 and earlier. Therefore you should not use this manual as a reference for Code39 Fontware.
Although font characters scale linearly and print any sizes required,
not all sizes will produce best quality barcodes. The reason is that printers
can only address individual pixels instead of a length specified in
inches or centimeters. For example, a printer dot measures 3.33 mils on
a 300-dpi printer. Certainly you can not print a size smaller than 3.33 mils.
And you can not consistently print a length of 5 mils, because this printer either
prints 3.33 mils, or 6.66 mils in this case. We call a font size optimal when the dots produced always remain constant. This
is vital to small size barcodes where the barcode quality largely depends on the
constant width of elements. On the other side, this is usually not a problem
when X dimension is big enough especially at normal sizes
(such as 15 and 20 mils).
The optimal sizes for this version Code39 fonts are integral times of 4 on a 300-dpi printer and integral times of 2 on a 600-dpi printer. To quickly locate the font size based on X-dimension requirement, use the table below:
Table 3.1. X Dimensions List
| Font Size | X Dimension | Font Size | X Dimension | ||
|---|---|---|---|---|---|
| 6 pt | 5 mils | 0.013 cm | 28 pt | 23 mils | 0.059 cm |
| 8 pt | 7 mils | 0.017 cm | 30 pt | 25 mils | 0.063 cm |
| 10 pt | 8 mils | 0.021 cm | 32 pt | 26 mils | 0.065 cm |
| 12 pt | 10 mils | 0.025 cm | 34 pt | 28 mils | 0.071 cm |
| 14 pt | 12 mils | 0.029 cm | 36 pt | 30 mils | 0.076 cm |
| 16 pt | 13 mils | 0.034 cm | 38 pt | 31 mils | 0.080 cm |
| 18 pt | 15 mils | 0.038 cm | 40 pt | 33 mils | 0.084 cm |
| 20 pt | 17 mils | 0.042 cm | 42 pt | 35 mils | 0.088 cm |
| 22 pt | 18 mils | 0.046 cm | 44 pt | 36 mils | 0.092 cm |
| 24 pt | 20 mils | 0.050 cm | 46 pt | 38 mils | 0.097 cm |
| 26 pt | 22 mils | 0.055 cm | 48 pt | 40 mils | 0.101 cm |
For example, suppose that X-dimension required is 15 mils, from Table 3.1, “X Dimensions List”, the optimal size is 18 points on 600-dpi printers, or 20 points. [2]
Many barcode standards require that a code 3 of 9 barcode to have a X-dimension at 7.5 mils or above on open systems. To meet this requirement, the font size should be at least 8 points.
Sometimes a requirement does not specify X-dimension. Instead, it gives the requirement of overall length or character per inch (cpi). Fortunately it is easy to derive X dimension from barcode length. A Code39 character always has 3 wide elements and 7 narrow elements [3]. When N (the ratio of the nominal wide element width to the nominal narrow-element width) is 3.0, the width of a code39 character is 16 times X dimension.
For example, assume that barcode density specified is is 8 characters per inch (including extra start and stop characters). It translates into 1/8" per character. Divide the value by 16 we get X dimension 0.008 inch. From the X-dimension table, assume that the printer has a resolution of 600 dpi, the font size to be used should be 10 points.
After font size is determined from the X dimension requirement, now it is time to find which font meets the bar height requirement. In this pack seven different bar heights at any given font size. At 12 points, the barcodes produced will have the following heights:
Table 3.2. Bar Heights of Code39 Fonts (at 12 points)
| Height Option | Bar Height (inch) | Bar Height (cm) |
|---|---|---|
| XXS | 0.125 inch | 0.318 cm |
| XS | 0.250 inch | 0.635 cm |
| S | 0.375 inch | 0.952 cm |
| M | 0.5 inch | 1.27 cm |
| T | 0.625 inch | 1.588 cm |
| XT | 0.750 inch | 1.90 cm |
| XXT | 1.0 inch | 2.54 cm |
Assume that you need a font to produce barcodes with X dimension at 15 mils and bar height at 1 inch. From the X dimension table 18 points should be used as the font size. At 18 points, T fonts produce bar height of 0.625X18/12=0.94 inch, whereas XT fonts produce bar height 0.75*18/12=1.125inch. Both are closest matches to the requirement. If requirement says that the bar height must be at least 1 inch, then XT fonts should be selected.
The last factor of font selection is human readable text. The human
readable text can be added using a text font. For convenience,
we create fonts with human readable text built-in. It is easy to
identify human-readable fonts - these fonts with names ending with a trailing letter A. Therefore, MRV Code39M produce barcodes only, whereas MRV Code39MA produces barcodes with human readable.
Except this difference, the two fonts are identical.
Fonts are easy to use and portable among systems. On the other side, font characters scale in both directions. That means it is impossible to get both sizes match the ones required. The bar height always scales up and down at the same time X-dimension scales up and down.
Code39 standard also allows customization of the ratio N. N is normally a value between 2.5 and 3.0. A lower value increases barcode density at the cost of readability. All code39 fonts included in this package have a fixed ratio of 3.0, which is required by most applications.
In consideration of the possible requirement to have the font customized for
specific needs, Morovia offers custom font services at reasonable cost. For example, we can
modify a font to have N=2.5, or have a font meet both bar height and X dimension requirements. Note that this service is offered only
to customers who already purchased a license of the font, and the license term
of the modified font follows the product to be replaced. If you have such needs,
please contact us at <support@morovia.com>.
[2] Note that 18 pt is not an optimal size for 300-dpi printer, although the barcode printed might pass scan testing.
[3] Some specifications say that a code39 character consists of 9 elements, among which 3 are wide. This is how the name "3 of 9" comes from. This statement is correct. However, it did not take the inter-character gap into count. According to the code39 standard, a blank element with equal to X-dimension is required between characters. To simplify the calculation, we count this element in the character.