I was quite surprised to find out today that antimensions also exist-although rare- in the Roman-rite.

http://www.religieuserfgoed.nl/objecten.aspx?ID=1495 (in Dutch)

You may click on the images to enlarge them.

http://www.orbiscatholicus.org/2010/01/when-there-is-no-altar-stone-mass-kit.html

In what context do they use them? Portable altars, as in the military chaplaincy?

Portable altars for priests on special missions, especially those in the military chaplaincy.

One priest of my (many many years) acquaintance was issued one for his hiking... he lead youth hikes every summer for more than a decade, hiking Resurrection Pass (37 miles, 5 days) on retreat. Have done it twice. It was placed under the corporal.

Latin priests have used small superaltars (altarium portatilium) as portable altars. They were usually made of stone or some other hard material, but I think that there were some made of cloth or fabric. After the liturgical reforms you don't need a superaltar to celebrate Mass.

The Latin Rite parish near me does not have a relic in its main altar and the priests don't use antimensions. The old parish altar had one and no one knows what happened to the altar from the old building.

I am planning to make one according to the 1947 rubrics...

I am curious. What do the 1947 rubrics say about making an antimension?

Actually the antimensium latinum is blessed, not consecrated.

There is also the alternative of using a Byzantine Antimension - which must be consecrated by a Greek-Catholic Bishop and is then issued to the requesting priest.

The Oriental Congregation used to issue Byzantine Antimensia; I don't know if they still do. One can obtain the necessary relics from the monastery in Rome, which parcels them for Antimensia.

The antimensium latinum is a twentieth-century development, and was primarily used by military chaplains. It largely fell out of use when the Novus Ordo was introduced and the requirement to have an altar stone or antimension was tacitly dropped - although it seems that this requirement may lawfully be ignored only per modum actus; for celebrations on a regular basis one should still have an altar stone or antimension.

Fr. Serge

1. BLESSING OF AN ANTIMENSION*

which by a special Apostolic indult may be used in the
celebration of Mass in mission territories, in place of an altar-
stone or portable altar

(Approved by the Congregation of Sacred Rites, March 12, 1947)

*Reserved to a bishop but may be delegated to a priest.

The bishop (or a priest delegated for this), having ascertained
the authenticity of the relics of holy martyrs to be used here,
encloses them in a tiny sack which is sewn in the right corner of the antimension. Then he blesses the antimension, saying:

P: Our help is in the name of the Lord.
All: Who made heaven and earth.
P: The Lord be with you.
All: May He also be with you.

Let us pray.
Lord, we humbly appeal to your sovereignty, asking that it please you to bless + this antimension, made ready by our lowly ministry to receive the offerings of your people. For on it we are to offer the holy Sacrifice to you, to the honor of the blessed Virgin Mary and all the saints, and in particular to the honor of Saints N. and N., whose relics we have enclosed therein. Grant that by these sacred mysteries the bonds of our sins be loosed, our stains blotted out, pardon obtained and graces acquired, so that together with your holy elect we may merit the joys of everlasting life through Christ our Lord.
All: Amen.

He sprinkles it with holy water.

From the 1964 Roman ritual

Didn't Fr. Januarius Izzo write the definitive book on Eastern and Western Antimensia?

For the Latin rite, it is always that a antimens is linen, with a small sack for the relics.

For the liturgies here, we use a antimens.. But I placed only one first class relic and four second class relics (vestment). But it was blessed by our Bishop in the Old Form of the Roman Rite (as seen above).

Oh yes, he did!

It was necessary for me to follow the rubrics... too..

Father's post was right...