Thread Subject: 1-G - Text size recommendations

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From: Schomburg, Paul
Date: Tue, Feb 26 2008 7:30 AM
Subject: 1-G - Text size recommendations

Folks: Panasonic reviewed the caption standards CEA-608 and CEA-708
that are referenced by the FCC rules. These requirements provide that
the display device must be able to display a total of 32 characters in a
single line. With a minimum size of 10 point text as required by 1-G
below, 32 characters can be displayed on as small as a 4.5" screen, but
smaller screen sizes would result in text below 10 points. Since this
requirement is fixed in FCC rules, and many source devices do not have
an integrated display (e.g. set-top boxes, etc.), there is no way for
such video source devices to state compliance for very small screen
sizes. Therefore, government agencies can best comply with this
requirement for closed captions by ensuring the screen used to display
video is larger than 4.5" diagonal, and I have added a note 6 to reflect
this.



I should also note that video source devices that are not covered by FCC
rules (e.g. media players without DTV tuners) may not be able to
guarantee compliance with this either. Such devices, such as DVD
players, rely on the author of the content source (i.e. the DVD disk) to
define the text font and size choices, which may or may not provide the
capability to adjust text size to compensate for small screen size. In
this case, content which is authored with CEA-608 or CEA-708 captions
(or functionally equivalent subtitles for the deaf & hard of hearing)
should not be ruled out of compliance either, because they will comply
when it is shown on displays larger than 4.5".



I would be happy to answer any questions on today's call.



Thanks, Paul



1-G - Text size (Recommended, No Quorum)

There must be at least one mode where all information that is required
for product use and is provided in text is readable by people with 20/20
vision at 3.5 times their typical viewing distance. This mode must be
the default mode unless the activation method for that mode can be done
at 3.5 times the typical viewing distance or the product automatically
sets itself to that mode for users who require it. This provision does
not apply to safety labels, regulatory labels, and marks that are not
required for product use. This requirement does not apply to the caption
decoding functions of products that are governed by U.S. Federal
Communications Commission (FCC) regulations 47 CFR 15.119 or to devices
which provide equivalent functionality as stipulated by 4-A - Caption
Processing (Consensed).

Note 1: Providing text in an accessible file on a device meets this
requirement for information that is not location specific (e.g. labels
are location specific).

Note 2: These are minimums and it is recommended that larger fonts be
used wherever possible on any product - either by default or as an
option.

Note 3: If other means of visually conveying the information in the
label or instructions exists (e.g. uniquely tactilely discernible
through shape), then the text is not "required for product use" and the
text size requirement does not apply.

Note 4: See also 3-D-User Preferences for software products that run on
operations systems that provide a function to set user preferences.

Note 5: One way this provision may be met by using type (or in pixel
dimensions converted from point size) that is:

1. For devices designed to be located in public places or for devices
used away from a person's workstation:
a) At least 12 points if text is a label and if the user can position
their face close to the label
b) At least 14 points for all other text

2. For devices designed to be located at a person's workstation:
a) At least 10 points if text is a label and if the user can position
their face close to the label
b) At least 12 points for all other text

where 1 point = 1/72.27 inches (on computer displays 1/72 inch).

Note 6: For display of captions this requirement can be met by ensuring
the screen used to display video is larger than 4.5" measured
diagonally.


Rationale(Added Feb 6)
The goal of this provision is to support people with low vision. People
with vision worse than 20/70 typically use an assistive device, so this
provision is aimed at supporting those with vision between 20/400 and
20/70.

* For people with 20/20 vision viewing text at 40 cm (15.7 inch),
8pt type is a small but acceptable type size.
* For people with 20/70 vision, an acceptable size is
approximately 28pts at 40 cm viewing distance.
* If we assume users with low vision can move in closer (half
distance - 20 cm) to view text (and that their glasses allow this), 14
pt type would provide type that subtends the same visual angle (as 28 pt
at 40 cm).

Note 5 provides type sizes that can be used to meet the requirements of
this provision. At a workstation, it is reasonable to assume that
special reading aids (such as a moderate magnifying glass) would be
available even if user's vision is in the range of 20/30 to 20/70, and
fonts can therefore be smaller. The sizes for devices designed to be
used away from a person's workstation are aimed at those with low vision
but not very low vision (beyond 20/70). This is based on an assumption
that:

* People with 20/70 vision or better would not usually carry a
magnifying device with them.
* People with worse than 20/70 vision would usually carry portable
optical magnifying devices (including special glasses) with them.





Paul G. Schomburg, Sr. Manager

Panasonic Corporation of North America

Government & Public Affairs

1130 Connecticut Ave., N.W., STE 1100

Washington DC, 20036

Tel: (202) 912-3800 x114; Cell: (202) 550-2230