Designing forms for auto field detection in Adobe® Acrobat®

Adobe Acrobat 9 Technical White Paper

Adobe Acrobat software (versions 8 and 9) has the ability to recognize form fields, making it faster and

easier to create dynamic forms in PDF. If you follow some basic guidelines when designing electronic

forms in authoring programs, such as Adobe InDesign® or Microsoft Word, you can significantly improve

the auto field detection process.

The auto field detection feature uses an algorithm to determine when field objects can be created in a

form. The algorithm can process electronic forms from scanned documents and certain native document

files. The detection process looks for the following types of form design elements:

• Underlines and boxes for ll-in areas

• Check boxes

• Radio buons

• Signature areas

• Comb elds

• Tables for ll-in areas

Auto field detection does not process combo boxes (sometimes called drop-down lists), list boxes,

and barcodes.

By following certain form design practices during the authoring process, you can significantly improve the

auto field detection results and substantially reduce the time it takes to develop interactive PDF forms.

Results of running auto eld detection on a le that has no existing form elds

Table of contents

2: e auto eld

detection process

3: Basic design layout

considerations

3: Design considerations

for specic

form objects

6: Troubleshooting

Designing forms for auto eld detection

in Adobe® Acrobat®

Create electronic forms more easily by using the right elements in

your authoring program to take advantage of automated features in

Acrobat 9

2

e auto eld detection process

Auto field detection was significantly improved in Acrobat 9 and the 9.1 update. To initiate the auto field

detection process on an existing PDF in Acrobat 9 choose Forms > Add or Edit Fields. In Acrobat 8

Professional, this feature was initially introduced as Run Form Field Recognition (Forms > Run Form

Field Recognition).

Next, a dialog box opens and prompts you to decide whether to run auto field detection. Clicking Yes

starts the automatic field detection process.

PDF documents that originate from scanned images automatically go through optical character

recognition (OCR) first. Running OCR does not modify the original content—the content still appears as

an image. The page only changes in the addition of form field annotations. The auto field detection

process can look for text including special characters, such as boxes, circles, and horizontal lines, from

fonts such as Zapf Dingbats, Wingdings, and Webdings. Graphic objects that are used to design forms,

such as horizontal and vertical lines and stroked rectangles, are also analyzed in scanned documents.

To process native documents, such as Word or InDesign files, for auto field detection, open the file using

the Acrobat 9 Form Wizard (Forms > Start Form Wizard) and select “An existing electronic document” in

the Create or Edit Form dialog box. The Form Wizard will convert the document to PDF and auto detect

form fields in one step.

Wizard dialog box

In existing PDF files (or native files that have been converted to PDF), the auto field detection process

looks for the same objects as scanned documents, as well as rectangles (hollow and filled), diagonal lines

forming a diamond-shaped appearance, and curved lines forming a circular appearance.

After form field detection, field names are assigned to each object. For objects such as underlines, text

boxes, and check boxes, the text adjacent to the form field is used as the name. For radio buttons, group

labels are used to determine the field names. Field names in a table are based on information inside the

cell or in the column header.

After the form fields are named, the actual form fields are created and the tab order is set based on the

interpreted reading order of the form. If the PDF is tagged for accessibility, new annotations are added to

the structure tree.

3

Basic design layout considerations

The auto field detection process looks for certain basic form design elements. To help improve the

process, here are some general tips to consider when authoring a form.

• Keep it simple and uncluered—use ample white space or separator lines between areas.

• Keep your layout well-organized so the eld tab order is set properly.

• Keep text within a 10–24-point size range.

• Avoid drop shadows or ornate graphics on text labels.

• Avoid overlapping elds, especially within areas that use underlines.

• Avoid heavy decorative graphics or transparency on the page. See www.peachpit.com/articles/

article.aspx?p=1271249 for tips on simplifying visually complex forms.

• Use white as the primary background color; avoid puing text on top of colored rectangles.

• Use the same style for each type of form object.

• Do not use the same text label across multiple elds.

• Make sure custom fonts use the proper encodings. In Acrobat 9 Pro or Acrobat 9 Pro Extended, you can

use the Preight tool to determine this.

Design considerations for specic form objects

The auto field detection feature looks for specific objects to convert to form fields. For example,

underlines, text boxes, and clearly delineated tables are converted to text fields. By default, text fields are

created with the font size set to Auto, which means text in the field will shrink to fit the field as data is

entered. The default font is Helvetica. Stroked square-, circular-, or diamond-shaped objects indicate check

boxes. Circular objects or numbered buttons adjacent to specific text labels indicate radio buttons, and the

word signat ure is interpreted as a digital signature field. When creating specific form objects during the

form authoring process, review the following suggestions to improve auto field detection.

4

Object Design considerations

Underline

First Name Last Name

-------------------------------------------------------------------

First Name Last Name

.................................................................................

Name:

• Use a solid, dashed, dotted, or dash-dot pattern for underlines.

You can create them with graphic lines, underscores, dashes, or

dot characters.

• Do not place dashes or slashes on top of the underlines,

for example:

• To create multiple fields from a single underline, place text labels

underneath that are well separated.

• Put text labels to the left of or below underlines, without letting

them touch the underlines; they will be used to create the

field names.

Text box

• Do not use drop shadows or decorative flourishes. Use fills

instead of wide strokes.

• Make sure text boxes do not touch other graphical elements in

the form.

• Watch point sizes in your designs; the text field height is

determined by adjacent objects, up to 36 points. A multiline text

field will be created if the text box area is taller than 36 points.

• Put text labels in the text box or to the left of or above the box;

they will be used to create the field names. For side-by-side

boxes, the text label must be in the left box with an empty box

to the right.

Check box

High School Diploma

Trade Certificate

Associate’s Degree

Bachelor’s Degree

Master’s Degree

Professional Degree

• Use stroked square-, circular-, or diamond-shaped objects to

designate check boxes.

• Make graphic objects symmetrical and uniform in appearance.

• You can use special characters from fonts such as Symbol, Zapf

Dingbats, Wingdings, and Webdings.

• Put text labels to the right of check box objects; they will be used

to create the field names.

Radio button

Group label

Salutation

Mr

Dr

Ms

Miss

Mrs

Group label

• Use circular objects or numbered buttons to in a single row or

column to indicate radio buttons.

• Use group labels to the left of or above each radio button

group—otherwise they will default to check boxes. Field names

are determined from the group labels and individual button

labels from the text to the right of each button.

• Use the following text labels to have radio buttons created

automatically: Yes/No, M/F, Male/Female, Jr/Sr, Mr/Mrs/Ms/

Miss/Dr.

• Use one of the following group labels to have radio buttons

created automatically: Salutation, Sex, Occupation.

Signature area

Signature

• Place the word Signature adjacent to an underline or text box to

have a signature field created.

5

Object Design considerations

Open comb field (no line on top)

• Design open comb fields in a U or an L shape (not touching if

L-shaped).

• Make tick marks between characters of the same height.

• Put text labels above, below, or to the left of open comb fields;

they will be used to create the field names.

• Avoid varying the dimension of individual cells, spacing, and

stroke weights.

Closed comb field (top line is drawn)

• Design closed comb fields to be adjacent or touching.

• Do not design fields excessively wide compared to height.

• Put text labels above, below, or to the left of closed comb fields;

they will be used to create the field names.

• Avoid varying the dimension of individual cells, spacing, and

stroke weights.

Table

• Use line rules to indicate cell borders (except outside borders).

Table cells must share the same border line.

• In tables like the one at left, put text labels in the top or left

portion of cells; they will be used to create the field names.

• In tables with rows and columns, put text labels in the row and

column headers to indicate what the field names should be. If

there are no row or column header labels, the field names

Row_M or Column_N will be used.

• Avoid excessive white space in table headers.

Although auto field detection can significantly reduce the time it takes to create an interactive form, not all

forms are suited for this feature. For forms that contain complex tables (with rows and columns that are

calculated), using hierarchical field names (such as total.0, total.1, and so on) makes it easier to calculate

formulas as well as duplicate and rename fields. Since the auto field detection process names the form

fields based on text labels next to the form objects, the field names are not hierarchical. Therefore, if you

have a form that requires hierarchical field names, you should manually insert them.

6

Troubleshooting

After running the auto field detection process on a form, check it to make sure the correct fields have been

created. You might need to perform some manual steps to complete the form. For example, date and

numeric fields are not automatically detected. Use Form Editing mode to add, edit, or delete fields.

Dialog box that appears when auto eld detection is complete

If auto field detection does not run on a particular form, review these troubleshooting tips:

• If you’re having diculty with a particular page, try using Document

>

Extract Pages, and then running

auto eld detection on the rest of the document.

• Make sure your document is not enabled for Adobe Reader® soware. If it is, use the File

>

Save a Copy

command to remove Reader enabling prior to running auto eld detection.

• Make sure your form does not have a security seing that prevents changes to the PDF. To check, choose

File > Properties and review the Security tab.

• Check whether the form was created using a PDF/A seing. is seing also prevents changes to the PDF.

To check, open the Navigation pane and see if the Standards navigation panel and icon appear.

Standards navigation panel

Adobe Systems Incorporated

345 Park Avenue

San Jose, CA 95110-2704

USA

www.adobe.com

• Certain metadata or document structures can interfere with the auto eld detection process. Use

the Examine Document feature (Document

>

Examine Document) in Acrobat to remove any

unnecessary content.

• If the document already has a few form elds, delete them before running auto eld detection. Save the

PDF prior to deleting the elds to avoid losing any unsaved work. You can deleteform elds from the

Fields navigation panel, which is available only while in Form Editing mode.

Once you have created a form with the help of auto field detection, you may find the need to update the

form at some point. Rather than starting from scratch, consider using the Document > Replace Pages

command in Acrobat to update pages as needed as a substantial time-saver.

Creating interactive PDF forms does not have to be a daunting task. By following some basic guidelines

during the form design stage, you can make auto field detection in Acrobat do much of the work and

significantly reduce the time it takes to produce your forms.

For more information

Product details: www.adobe.com/go/acroba t

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